You ask a question.

It gives you an answer.

You ask it to rewrite an email, summarize a document, plan a trip, or explain something you do not understand.

That is already useful.

But it is not the main reason people in technology are suddenly so excited about AI agents.

The real shift is that AI is beginning to move beyond answering questions.

It can now increasingly:

• Inspect your files

• Understand a larger project

• Use different tools

• Perform several steps in sequence

• Create and edit documents

• Check its own work

• Continue until it reaches a result

Instead of merely telling you what to do, it can begin doing the work with you.

That is the hype around AI agents.

And tools like Claude Code and Claude Cowork offer one of the clearest previews of what this new way of working may look like.

Why I Am Writing About This

Before getting into how these tools work, I want to explain why I feel qualified to talk about them.

I work professionally as a software engineer, where I use AI tools as part of real projects rather than only experimenting with them for fun.

I have been using Claude Code extensively since it first became available, both professionally and in my free time. Over the last year, it has become a major part of how I build software, investigate problems, understand complex systems, automate processes, and get work done, both professionally and personally.

But my interest in this area started before Claude Code.

For years, I have been studying large language models, following developments in AI, keeping up with new research and product releases, and trying new tools as they become available.

More importantly, I try to understand where these technologies are genuinely useful.

There is always plenty of hype around AI. Every week, a new product promises to transform the way we work.

I am less interested in the announcements themselves than in what happens when you actually use these tools every day:

• Which ones meaningfully improve your work?

• Which tasks should you delegate?

• Where do they still fail?

• Which improvements survive once the initial excitement disappears?

• How can someone use them without being deeply technical?

Outside of my professional work, I use AI across large parts of my personal life.

It has helped me:

• Research and organize ideas

• Build personal tools

• Improve how I learn

• Plan projects

• Help me understand and make better decisions

• Process large amounts of information

• Run and grow this newsletter

• Automate repetitive work

• Create systems around tasks I previously handled manually

Over time, AI stopped feeling like a website I occasionally opened.

It became closer to an additional layer across much of the work I already do.

That is why I want to bring the ideas behind tools like Claude Code and Cowork to a broader audience.

You do not need to understand programming to understand these tools.

What Is an AI Agent?

The word “agent” makes the technology sound more complicated than it needs to be.

I think the easiest way to understand it is this:

A chatbot gives you an answer. An agent works toward an outcome.

Imagine asking a normal AI chatbot to help you organize your personal finances.

It might suggest that you:

• Export your bank transactions

• Group them into categories

• Identify unnecessary subscriptions

• Create a monthly budget

• Build a savings plan

That advice might be good.

But you still need to do everything yourself.

You need to download the files, open the spreadsheet, clean the data, create the categories, perform the calculations, format the results, and decide what comes next.

An AI agent can potentially take on much more of that process.

You give it the relevant files and explain what you want.

It can inspect the information, organize it, create the spreadsheet, find recurring expenses, produce a report, and tell you which areas deserve your attention.

Why This Is a Bigger Shift Than Better Chatbots

Most meaningful work does not fit into a single prompt.

Real projects usually require several steps:

1. Understand the situation

2. Find the relevant information

3. Make a plan

4. Create something

5. Review the result

6. Fix what went wrong

7. Present the final version

Traditional AI mostly helps with isolated parts of that process.

An agent can increasingly connect them.

Instead of asking:

How should I organize these documents?

You can ask:

Review the documents in this folder, group them by topic, rename them consistently, create a clear folder structure, and produce an index showing where everything is stored.

Instead of asking:

How can I study for this exam?

You can ask:

Review my lecture slides, notes, exam date, and current progress. Create a realistic study plan, divide it into weekly sessions, produce practice questions, and build a tracker I can use to measure my progress.

Instead of asking:

What should I write about next?

You can ask:

Review my previous articles, audience feedback, unfinished drafts, and content ideas. Identify recurring themes, find gaps in what I have covered, and create a ranked list of future topics.

Why Claude Code Became So Popular

Anthropic’s Claude Code was initially built for software development.

It allows Claude to work directly inside a project rather than waiting for someone to paste small pieces of information into a chat.

It can inspect files, understand how different parts relate to each other, make changes, run tests, notice errors, and revise its approach.

For programmers, this is a major improvement.

A traditional chatbot might explain how a feature should be built.

Claude Code can often help build the feature itself.

It can:

• Explore an unfamiliar project

• Find where a problem originates

• Make changes across multiple files

• Test whether those changes work

• Explain what it changed

• Continue improving the result

The important change is not simply that it writes better code.

It is that it can operate inside the environment where the work happens.

It sees more context, has access to more tools, and can complete a much larger portion of the task.

Anthropic Is Not the Only Company Building This

Claude Code and Cowork are not the only agentic tools available.

OpenAI has Codex, which follows a similar broader direction. It began with a strong focus on software development but is increasingly being used for research, data analysis, reports, spreadsheets, presentations, automation, and lightweight internal tools.

Other companies are building their own versions, and many existing AI products are gradually adding agent-like abilities.

The important thing is not to become attached to one company or interface.

It is to understand the underlying shift:

AI is moving from generating individual responses to completing larger pieces of work.

I am focusing mainly on Claude Code and Claude Cowork here because Anthropic’s products are receiving a lot of attention right now.

They are useful examples for explaining how this new category works.

But the larger idea applies far beyond Claude.

Claude Code Is Not Only About Code

The name makes it sound like a niche tool for developers.

And today, programming is still one of its strongest uses.

But the more important idea is not code.

It is delegation.

Claude Code showed that AI can be given access to a larger environment, understand what is inside it, and perform a series of connected actions.

That same model can apply to almost any type of computer work.

A creator does not only write.

They also research, organize ideas, manage files, review analytics, repurpose content, plan publishing schedules, and track unfinished work.

A student does not only study.

They collect material, create notes, plan revision sessions, identify weak areas, generate exercises, and monitor progress.

A small business owner does not only sell.

They process customer feedback, prepare reports, organize documents, write proposals, update spreadsheets, and create repeatable processes.

Most work is made up of these small connected tasks.

Where Claude Cowork Fits In

Claude Cowork takes the basic idea behind Claude Code and makes it more accessible for general work.

Claude Code is strongest when working with software projects, technical files, and custom tools.

Cowork is aimed more broadly at documents, research, spreadsheets, folders, presentations, and everyday knowledge work.

The distinction can be simplified like this:

• Claude Chat helps you think, write, explain, and answer questions.

• Claude Code helps you build, change, and operate technical projects.

• Claude Cowork helps you delegate broader work involving files, information, and multi-step processes.

There is plenty of overlap between them.

A non-programmer might still use Claude Code to build a small personal tool.

A programmer might use Cowork to analyze research or prepare a presentation.

The labels matter less than the change in how you interact with the AI.

You are no longer limited to asking it for a block of text.

You can give it a workspace and an outcome.

What Everyday People Can Do With AI Agents

You do not need to automate your entire life.

You do not need to understand programming.

You do not need to start by building some complex system.

The best place to begin is usually a task you already find annoying.

Organize Your Digital Life

An agent could help you:

• Sort years of documents

• Rename files consistently

• Find duplicates

• Create an index of important records

• Organize receipts

• Summarize large folders

• Identify missing information

• Create a cleaner folder structure

This is not exciting work.

That is exactly why it is useful to delegate.

Build a Personal Learning System

You could give an agent your notes, course materials, saved articles, and learning goals.

It could then:

• Group the material by topic

• Find gaps in your understanding

• Create a study schedule

• Generate practice questions

• Turn notes into flashcards

• Build a progress tracker

• Explain difficult ideas at different levels

A chatbot can explain one topic.

An agent can help create the system around your learning.

Improve Your Career

Someone applying for jobs could use an agent to:

• Organize previous projects

• Extract achievements from old documents

• Compare job descriptions

• Adapt a CV for different positions

• Create interview questions

• Track applications

• Identify commonly requested skills

• Prepare a structured development plan

You still decide which job you want and how you present yourself.

But much of the surrounding preparation can be accelerated.

Run a Small Business

A freelancer or small business owner could use agents to:

• Analyze customer feedback

• Prepare recurring reports

• Clean and organize spreadsheets

• Turn meetings into action lists

• Draft proposals based on previous work

• Create operating procedures

• Organize client folders

• Build simple internal tools

• Track recurring administrative tasks

Large companies have always had employees and custom software to handle this kind of work.

AI is beginning to give individuals access to some of the same leverage.

Support Creative Work

A creator could provide previous articles, transcripts, audience comments, analytics, and unfinished ideas.

An agent could:

• Group ideas into themes

• Find repeated audience questions

• Identify missing topics

• Create outlines

• Organize research

• Repurpose longer content

• Maintain an editorial calendar

• Compare the performance of previous work

I do not think the goal should be to have AI generate an endless stream of generic content.

The better use is to reduce the administrative and mechanical work around creating.

That leaves more time for the parts that still require your taste, experience, judgment, and point of view.

The Real Skill Is Learning to Delegate

People often assume that getting good results from AI is about writing clever prompts.

Prompts matter.

But the more important skill is understanding the work well enough to delegate it.

You need to know:

• What outcome you want

• Which information is relevant

• What rules the agent should follow

• What it is allowed to change

• What it should leave untouched

• How the result will be checked

• Where human judgment is still required

This is surprisingly similar to managing another person.

A vague request produces vague work.

“Organize this” leaves too much room for interpretation.

A better instruction might be:

Review all the files in this folder and explain what you find. Propose a clear organization system before making any changes. Do not delete or overwrite the originals. Create the new structure in a separate folder, rename files consistently, and produce an index explaining where everything belongs. At the end, flag anything you were uncertain about.

That instruction provides:

• Context

• A clear outcome

• Boundaries

• A planning step

• A safety rule

• A way to review the result

As AI becomes more capable, the quality of your delegation becomes more important.

The Bigger Picture

For most of the history of personal computing, we have adapted ourselves to software.

Someone built a program and decided how it should work.

We learned the interface and changed our process to fit its limitations.

AI agents begin to reverse that relationship:

Instead of searching for the perfect application, you can increasingly describe what you need and have AI operate or create a system around your process.

I think this is the real reason people are excited: Individuals are gaining access to a new form of leverage.

You can increasingly hand a computer an outcome instead of a sequence of clicks.

It is becoming a new category of software.

We are still early, so the tools are imperfect. Many current workflows will look primitive within a few years.

But the direction is clear.

AI is moving from answering questions to completing work.

And the people who benefit most will not necessarily be the most technical.

They will be the people who can recognize a repeatable problem, describe the desired outcome clearly, provide the right context, and judge whether the result is actually good.

If enough people are interested, I can write a follow-up article, in which I will go deeper into the practical side:

• How I personally use Claude Code and Cowork

• Which tasks are worth delegating

• Specific workflows for everyday life and work

• Prompts that produce better results

• How to set boundaries and avoid costly mistakes

• How to identify your first useful automation

Let me know if you would like to read that.

Thanks for reading as always :)

I will see you next time!

— Tobi

Saving time should not be the final goal of using AI.

But that creates an obvious question:

What should you actually do with the time AI gives back?

Without a system, recovered time tends to disappear.

You finish a task 45 minutes early. Then you:

• Check your messages

• Open your inbox

• Answer a few emails

• Complete several minor tasks

• Somehow lose the entire 45 minutes

Nothing important improved.

So this article is about building a practical process for what happens after AI makes something faster.

The AI Reinvestment Rule

Before using AI to speed up a task, complete this sentence:

Read more

The result was good. Everything worked. I reviewed it, made a few small changes, and caught myself reaching for the laptop lid.

Task finished early. Time saved. Reward collected.

But then a question crossed my mind:

Saved for what?

That afternoon did not go into a bank account. I could not store it and withdraw it next month. The time was simply there, suddenly unoccupied.

And without a clear plan, I probably would have spent part of it scrolling through my phone, checking messages, or doing some other low-value task.

I had treated the recovered time as the reward.

But the recovered time was not the reward. The time freed itself is not the benefit.

This is a trap hidden inside the promise almost every AI product makes:

Save time.

It sounds like the finish line. But I would argue it is only half a sentence.

Saving time matters only when you know what you are saving it for.

You Cannot Actually Save Time

Money can be saved.

You can leave it in an account today and spend it five years from now.

Time does not work like that.

When AI gives you two hours back, those hours immediately begin disappearing. You will spend them whether you make a conscious decision or not.

And without a plan, time usually flows toward whatever requires the least effort:

• Scrolling.

• Checking emails.

• Watching another video.

• Doing smaller, easier tasks.

So saving time should never be the final goal.

The real question is:

What will you do with the time AI gives back to you?

I believe there are three valuable answers:

1. Improve the quality of your work.

2. Explore more options before deciding.

3. Take on a bigger problem.

Do one of these, and AI makes you more capable.

Do none of them, and AI only helps you become unproductive faster.

1. Reinvest the Time Into Quality

The most common way people use AI is simple:

• They finish the same work faster and stop as soon as it looks acceptable.

• The first draft is readable, so they publish it.

• The presentation is complete, so they send it.

The task works, so they move on.

But what if “finished” should no longer be the finish line?

What if it should become the new starting point?

AI can help me write a rough version of a newsletter much faster than before. But that does not mean I should publish the first decent result.

It means I can spend more time strengthening the argument, rewriting weak sections, finding better examples, and removing anything that does not deserve the reader’s attention.

The version AI helps me reach quickly should be the first version I used to begin with, not the version I send.

The same applies to almost any kind of work.

• AI can help you prepare a presentation faster. Use the remaining time to make the message clearer.

• It can help you write an email. Use the remaining time to make sure the other person will understand it correctly.

• It can help you research a topic. Use the remaining time to question the sources and examine what might be missing.

• It can help you create a business plan. Use the remaining time to test the assumptions behind it.

There is a large difference between something that looks right and something that actually is right.

That gap is where the saved time should go.

When the work becomes faster, the standard should also rise with it.

If your speed doubles while the quality stays exactly the same, you have not necessarily improved. You have simply finished sooner.

2. Spend the Time Exploring More Options

Before AI, exploring multiple ideas was expensive.

Creating one plan might take hours. Creating three could take an entire day. So most people followed the first reasonable idea they had and called it decisiveness.

You chose the first option because it was the only one you had enough time to explore.

AI changes that.

You can now compare several approaches before committing to one.

Instead of asking AI to write one headline, ask for twenty.

Instead of building your business around the first idea that sounds promising, compare five different versions of it.

Instead of accepting the first solution to a problem at work, explore three approaches and examine the strengths and weaknesses of each one.

Instead of writing the first newsletter angle that comes to mind, generate ten angles, reject nine, and develop the strongest one.

This is one of the most underused benefits of AI.

Most people use it to reach their first answer faster.

A better use is to delay the final answer until you have seen more possibilities.

Of course, AI should not make every decision for you.

It can organize the options. It can point out trade-offs. It can help you notice possibilities you may have missed.

But important decisions still require your judgment.

AI can show you different careers. It cannot decide what kind of life you want.

It can compare business ideas. It cannot decide which problem you care enough about to spend years solving.

It can suggest what to write. It cannot decide what you genuinely believe.

3. Use the Time to Take On a Bigger Problem

This is the most valuable option, and probably the least common.

When a task becomes easier, the natural reaction is to do more of the same task.

But the better response is often to move up to a more difficult one.

I actually think you can compare this with training in the gym:

When a weight becomes easy, you do not continue lifting the same weight forever and celebrate how quickly you finished.

You add more weight.

That is how progress works.

The moment your current level becomes comfortable, you increase the challenge.

The same principle applies to work and life.

If AI makes your existing responsibilities easier, perhaps the goal should not be to complete the same responsibilities with less effort forever.

Perhaps the goal should be to attempt something that previously felt too difficult, slow, or expensive.

• Start the business you never had time to build.

• Learn the skill you kept postponing.

• Create the project that once required resources you did not have.

• Give more attention to the work that requires judgment, creativity, empathy, and personal experience.

• Solve the bigger problem.

This principle has shaped much of my own life.

When I worked in banking, I did not simply try to become faster at the same tasks. I spent evenings and weekends learning software development because it opened the door to more difficult and interesting problems.

When my schedule became more efficient, I did not use every recovered hour for entertainment. I used part of it to combine full-time work, university, writing this newsletter, training, and learning Japanese.

Not every free hour needs to become productive. Rest, relationships, and enjoyment matter.

But there is a difference between choosing to rest and losing time because you never decided what it was for.

The Rule in One Sentence

Stop asking how much time AI saved you.

Ask what you spent that time on.

• Did you improve the quality?

• Did you explore better options?

• Did you take on a more important problem?

• Did you deliberately use the time to rest, think, or be with people you care about?

All of these can be valuable.

But if the answer is “nothing,” AI did not really save you anything.

It only shortened the period before the time disappeared somewhere else.

One Thing to Try This Week

The next time AI finishes something faster than expected, do not immediately close the laptop.

Pause and choose one of these:

Quality

Use the recovered time to make the result meaningfully better.

Do not just correct obvious mistakes. Improve the argument, simplify the explanation, check the details, and raise the standard.

Options

Create three alternatives you would not normally have had time to explore.

Compare them before committing to your first idea.

Importance

Move on to a larger problem that previously felt too time-consuming.

Use the new capacity to attempt work that was once out of reach.

The promise of AI is that it will free your time for the things that matter. Which is exactly the motto of this newsletter Output Theory.

The time AI gives you is worth exactly what you put into it.

Put something worthwhile in.

See you next Saturday.

— Tobi

Today, more than 10,000 people are subscribed.

The newsletter was never meant to replace my income within a year.

I started it while working full-time as a software developer and studying computer science at university. During that time, I was also learning Japanese, training regularly and traveling, amongst other hobbies and pursuits.

This was always a side project.

I wanted to become a better writer, share what I was learning, and slowly build an audience around ideas I genuinely cared about.

A year later, the audience has grown much faster than I expected.

Along the way, I have learned a lot about how newsletters actually grow, what makes readers return, and which creator problems are mostly distractions.

These are the principles that made the biggest difference.

Read more

It also estimates my pace of aging at 0.0x, which would technically mean I’m not aging at all.

That is obviously not literally true.

Biological age scores from wearables are estimates, not perfect measurements of how old your body really is. But they can still be useful. They combine several health and fitness metrics into a simple number that shows whether your current lifestyle is moving you in the right direction.

And according to the data, mine is.

I have tracked my health using blood tests, Oura, WHOOP, and other measurements for almost five years. Over that time, I’ve watched my resting heart rate decrease, my cardiovascular fitness improve, and my recovery become more consistent.

For most of my life, I never thought deeply about health.

I didn’t deliberately structure my life around longevity. Sleep was something that happened at the end of the day. Nutrition was mostly about what tasted good. Cardio was something I knew I should probably do more of.

That changed over the last few years.

Health gradually became one of my highest priorities. And that’s not because I became obsessed with living forever, but because better health improves almost everything else: energy, focus, mood, confidence, performance, and quality of life.

The biological-age score is simply one reflection of that.

Here are the habits that have made the biggest difference for me.

What Biological Age Actually Measures

Your chronological age is simple: it is the number of years since you were born.

Your biological age tries to estimate how quickly your body is aging based on your current health and physical condition.

WHOOP’s Healthspan feature uses factors such as:

• VO₂ max

• Resting heart rate

• Sleep consistency

• Lean body mass

• Activity levels

• Strength and fitness indicators

The exact number should not be treated as a medical diagnosis. It is better understood as a health score.

A lower biological age does not mean you have discovered the fountain of youth. It means your current biomarkers resemble those usually found in a younger or healthier person.

The real goal is also not to win a wearable leaderboard, but rather to improve the underlying metrics.

And most of those metrics respond to the same basic principles.

1. Treat Sleep as the Foundation

I have been slightly obsessed with sleep for several years.

And I still believe it is the number-one health lever most people could improve.

Sleep affects almost everything else you are trying to optimize:

• Exercise performance

• Hunger and appetite

• Blood sugar regulation

• Hormonal health

• Mental clarity

• Emotional stability

• Physical recovery

When you sleep badly, every other healthy behavior becomes harder.

You crave more calorie-dense food. You have less motivation to train. Your body recovers more slowly. Your stress tolerance drops. Even simple decisions require more effort.

Good sleep has the opposite effect. It makes the rest of your health system easier to maintain.

I have already written a full article about improving sleep here, so I will keep the practical advice simple:

• Aim for at least seven to eight hours.

• Try to sleep and wake at consistent times.

• Keep your bedroom dark, quiet, and cool.

• Avoid eating large meals shortly before bed.

• Reduce bright light and stimulation late at night.

There is no expensive supplement or futuristic device required. But if your sleep is inconsistent, optimizing smaller details will produce limited results.

2. Build a High Level of Everyday Movement

Exercise is the next major lever.

Personally, I lift weights around three to five times per week. I also spend roughly ten hours per week in lower and moderate heart-rate zones.

Most of that is not structured cardio.

It comes from walking, hiking, swimming, volleyball, outdoor activities, and simply moving throughout the day.

Many people think exercise only counts when they are wearing gym clothes, following a program, and suffering through a dedicated workout.

But your body does not care whether the movement came from a treadmill or a hike with friends.

It all counts.

Formal workouts are important, but they only occupy a small percentage of your week. Your general activity level fills the rest.

That is why I place so much value on walking.

On a bad day, I still try to reach around 10,000 steps. My average over the last few months has consistently been closer to 15,000, often way over that.

You do not need to hit an arbitrary number every single day. The goal is to keep your average high.

Walking is one of the most underrated health habits because it is:

• Easy to recover from

• Accessible to almost everyone

• Compatible with work and social activities

• Effective for increasing energy expenditure

• Helpful for cardiovascular and metabolic health

I also won’t get into the details here, but if it interests you, here is another blog article I wrote about how to get more steps in every day.

3. Prioritize Protein and Control Total Calories

Nutrition can become unnecessarily complicated.

People debate meal timing, fasting windows, individual ingredients, artificial sweeteners, seed oils, carbohydrates, and hundreds of different supplements.

But most people would improve their diet significantly by focusing on two priorities:

Eat enough protein.

Avoid consistently overeating calories.

Protein is not a miracle macronutrient. But it makes almost everything else easier.

It supports muscle growth and maintenance, especially when combined with resistance training. It also tends to be highly satiating, which makes controlling total calorie intake easier.

When your meals contain a meaningful amount of protein, you are less likely to spend the rest of the day constantly hungry.

And when you are less hungry, you have less room to overeat highly processed foods, sugar, and empty calories. Thus you will almost automatically improve your body composition.

A healthier body composition improves many of the biomarkers associated with long-term health.

From there, you can improve the details.

Eat a varied diet. Base most meals around whole or minimally processed foods. Include fruits, vegetables, healthy fats, and sufficient fiber.

But do not make perfection the goal.

I probably eat well around 80% of the time, but I still eat dessert some times. I go to restaurants. I travel. I drink occasionally. Sometimes I overeat.

The difference is that I notice when it happens.

If I eat far more than usual for a day or two, I naturally regulate my intake afterward. I do not punish myself or follow an extreme detox. I simply return to my normal routine.

4. Use the Sauna Regularly

I recently returned from an exchange semester in Helsinki.

Unsurprisingly, Finland turned me into a sauna enthusiast.

Before moving there, sauna was an occasional wellness activity. In Helsinki, it became part of my weekly routine.

And over time, I noticed improvements in my cardiovascular and recovery data.

A sauna exposes your body to heat stress. Your heart rate increases, blood vessels dilate, and your body works to cool itself through sweating.

In that sense, sauna use creates some of the same acute responses as exercise.

And people who currently exercise very little may notice especially significant benefits because the heat still places a manageable demand on the cardiovascular system.

Use sauna as an extra layer though, not as an excuse to avoid moving.

5. Limit Alcohol Before It Disrupts Everything Else

Alcohol is worth mentioning because its damage goes beyond the calories in the drink.

It makes most other healthy behaviors harder, too.

Over the last six months in Helsinki, I certainly drank more than I normally would. That was part of the social experience, and I do not regret it.

But I can also see the impact in my data.

Alcohol does not need to be banned completely. The important thing is to be honest about the trade-off. If you drink occasionally and deliberately, it probably will not destroy your health.

If drinking becomes a frequent default however, it starts weakening the entire system supporting your health:

One bad night becomes bad sleep. Bad sleep becomes a skipped workout.

The skipped workout becomes low movement and poor food choices.

One decision creates several others.

That is why reducing alcohol often produces benefits far beyond alcohol itself.

6. Keep Stress Low Enough to Recover

Stress is not always bad.

Exercise is stress. Learning is stress. Taking on difficult projects is stress. Short periods of pressure can help you grow.

The problem is remaining in that state without recovering.

Your body needs periods of activation and periods of rest.

This is another reason sleep, walking, social connection, outdoor activity, and sauna can be so useful. They help move you out of constant stimulation and into recovery.

I actually think you do not need a completely stress-free life. That would probably be boring and unproductive.

But you need the capacity to handle stress, followed by enough recovery to adapt to it.

Stop Optimizing the Final 5%

Health content online tends to focus on extremes, like complicated supplement stacks, ice baths, CGMs, highly specific training programs etc…

But they are the final 5%. The first 95% is much less exciting:

• Sleep enough.

• Move every day.

• Lift weights.

• Train your heart.

• Eat enough protein.

• Control your calorie intake.

• Limit alcohol.

• Manage stress.

Repeat for years.

Most people do not really need another health hack, but rather they need to become more consistent with the principles they already know.

The Bottom Line

My biological age of 18.8 is not the result of one supplement, workout, or secret routine.

It is the combined result of hundreds of relatively boring decisions.

• Going to bed early.

• Walking instead of taking the car.

• Choosing a protein-heavy meal.

• Lifting weights even when the session is not perfect.

• Drinking less often.

• Using the sauna consistently.

• Returning to the routine after falling off.

Do not start with the complicated details.

Build the foundation first.

Then keep it long enough for the results to become visible.

Because the goal is not merely to achieve a lower number on a dashboard.

The goal is to remain capable, energetic, and healthy for as much of your life as possible.

Thanks for reading.

See you next Saturday.

— Tobi

💡 Question: What are some things you applied to improve your health?

Leave a comment

That framing is wrong.

Focus degrades with neglect and improves with practice, exactly like physical fitness. The difference is that most people are doing the equivalent of never going to the gym, then wondering why they can't lift anything.

Why it's getting harder

This isn't nostalgia. The environment has changed in measurable ways.

The average person unlocks their phone 100+ times a day. Average time before task-switching has shortened. Notifications and feeds are designed by some of the smartest engineers on the planet to interrupt you.

Your attention isn't being lost. It's being harvested.

Every context switch (phone check, Slack ping, tab hop) carries a cost. Researchers call it attention residue: the mental trace of the previous task that lingers in working memory. That residue accumulates, and it costs you the deep, focused state where your best work actually happens.

The training model

Your prefrontal cortex (the part responsible for sustained attention and resisting distraction) is trainable.

Every time you resist a distraction and return to the task, you're doing a rep. Every time you give in, you're skipping the gym.

Consistency builds capacity. Inconsistency erodes it.

This means building focus isn't primarily about motivation or willpower. It's about training. Short sessions, consistent effort, progressive overload over time.

What actually works

Start shorter than you think you should.

If you can currently focus for 20 minutes before your brain wants out, start there. Not 90 minutes. Trying to jump straight to three-hour blocks is like walking into a gym and immediately trying to bench your max. You'll fail, feel bad, and stop. Build the rep range first. Add weight slowly.

Create a clear start ritual.

Your brain needs a cue that says "deep work now." Mine is simple: phone across the room, same playlist on, single tab open, timer set. Those four steps in order are the cue. My brain starts to focus before I've even looked at the task. Rituals compress warm-up time.

Work in blocks, rest between them.

The goal isn't to focus as long as possible. The goal is to recover and do it again. A strong 90-minute block followed by a 20-minute real break beats four scattered hours half-focused. Real rest means away from screens, not pseudo-rest where you're doom-scrolling and calling it a break.

Track your sessions.

Not obsessively. Just enough to build data. I keep a simple note: date, task, duration, quality rating 1-3. That feedback loop reveals patterns. When you consistently score a 3 on Tuesday mornings after good sleep, you start protecting Tuesday mornings. When you consistently score a 1 after lunch, you stop scheduling deep work after lunch.

Protect the environment.

Willpower is finite. The fewer friction-free exits available, the easier focus becomes. Remove your phone from your workspace. Block distracting sites during deep work. Close Slack. Small environmental changes beat massive willpower expenditures every single time.

The compound effect

It doesn't feel different from day one to day ten. But from day one to month six, it's a different brain.

Faster entry into deep work. More tolerance for sitting with hard problems. Less pull from distractions. These are real changes, not in personality, but in wiring.

Habits of attention reshape neural pathways. What starts as effortful gradually becomes default.

The honest part

The biggest focus killer in most people's lives is their phone.

Not their job. Not their colleagues. Not the open-plan office.

Their phone, because it's designed to interrupt, and most people have given it unlimited access to their attention.

The simplest thing you can do today: put your phone in another room during your most important work hours.

Not in your pocket. Not face-down on the desk. Another room.

You'll feel the difference immediately.

The minimal practice

Pick one 45-minute block in the morning. One clear task, no switching. Phone out of reach, distractions closed. No exceptions for that block.

Do it five days in a row.

The capacity comes back faster than you'd expect.

— Tobi

Someone decides they want to change. They get motivated. They go hard: 2-hour workouts, 4-hour study sessions, complete diet overhaul, new morning routine.

For about a week.

Then life happens. One day gets skipped. Then another. Then the whole thing collapses. Two months later, they’re back to the starting point.

This isn’t a failure due to willpower. It’s because of strategy.

Intensity without consistency is almost always a dead end.

The math of compounding

1% better every day compounds to 37x better over a year. 1% worse every day compounds to nearly zero.

But here’s what gets missed in the “1% daily improvement” framing: the compounding only works if you actually show up daily.

Five days of 5% improvement followed by a crash doesn’t compound. Steady, consistent, unremarkable effort repeated every single day is what creates the curve.

The power isn’t in the intensity of any single session. The power is in the continuity.

Why intensity feels better than it is

Intensity has a seductive quality that consistency doesn’t. A brutal workout, a 12-hour study session, a full weekend on a project. These feel productive. They feel like they’re moving the needle.

And they do move it. But only if the next session also happens.

What high-intensity efforts often do instead: create soreness and fatigue that forces days of rest afterward, set an unsustainable standard that makes future sessions feel like failure by comparison, drain motivation because the effort was so high that the brain flags it as too costly to repeat.

Intensity is a tool. The problem is when it becomes the strategy.

The consistent 70%

Three 45-minute training sessions every week, without fail, builds more over a year than six 2-hour sessions followed by a two-month gap.

30 minutes of language practice daily moves faster than 4-hour Saturday cramming sessions every few weeks.

The math works out because results aren’t linear with effort. They’re a function of accumulated effort over time. And accumulated effort requires continuity.

The “don’t break the chain” principle

Jerry Seinfeld reportedly used a simple system: mark an X on a calendar for every day he wrote jokes. The goal was just to not break the chain.

The point was not the output on any given day. The streak was.

This is psychologically powerful for a few reasons. It makes the daily action feel non-negotiable: you don’t ask “do I feel like it today?” you ask “how short can I make today’s session and still mark the X?” It creates momentum. A long chain is a visual identity commitment and the longer it gets, the less you want to break it. And it reframes what counts. A 15-minute session on a bad day keeps the chain alive. Without the chain mindset, you’d skip it entirely.

The chain does the work that motivation can’t.

The minimum viable dose

Every habit needs a floor: the version so small there’s no legitimate excuse not to do it.

For fitness: 10 push-ups. For reading: one page. For writing: one paragraph. For language learning: 5 flashcards.

I found that the biggest threat to consistency isn’t busy days. It’s the all-or-nothing mindset.

“If I can’t do the full workout, why bother at all?”

That’s the thinking that is problematic. The “minimum viable dose” kills that logic. You always do something. Even when everything else is falling apart.

Something beats nothing. Always.

And often, starting with the minimum leads to doing more anyway.

The long enough timeframe

Consistency only shows its power over time.

At one month, a consistent habit might not look dramatically different from an inconsistent one. At six months, the gap is noticeable. At two years, it’s compounded into a structural advantage.

Most people give up somewhere in month two, when the effort is real but the results aren’t visible yet. This is the so-called “valley of despair” in every compounding curve.

The people who make it through aren’t necessarily more talented or disciplined. They’re just playing a longer game. They’ve internalized that the visible results come after the invisible investment, not during it.

What this means in practice

Choose consistency over ambition when designing habits.

Not “I’ll train 6 days a week” when you currently go zero times. Start with twice. Add a third when twice is automatic.

Not “I’ll read an hour every night” when you currently don’t read at all. Start with 10 minutes.

Not “I’ll invest €1,000 per month” before you’ve built the saving habit. Start with whatever you won’t notice missing.

Then stay consistent.

Because consistent and small, across years, is how the remarkable things get built.

Thanks for reading!

— Tobi

The answer isn’t some exotic supplement stack.

It’s sleep.

More specifically: treating sleep like a performance system, not an afterthought.

If you want consistent energy, creativity, and output, sleep isn’t optional. It’s the basis.

Today I’ll break down exactly how I’ve engineered my sleep so I’m rarely tired, even when life is busy.

Why This Matters More Than You Think

Sleep is not just rest.

It’s:

• Hormone regulation

• Memory consolidation

• Emotional processing

• Muscle recovery

• Cognitive sharpening

You can train hard, eat clean, optimize productivity systems… but if your sleep is chaotic, everything downstream suffers.

And here’s the uncomfortable truth:

Most people don’t have an energy problem.
They have a sleep discipline problem.

Why Most People Stay Tired

Three common mistakes:

• Phone in bed.

• Caffeine too late.

• Inconsistent sleep environment.

Add heavy meals at night, irregular wake times, and random scrolling until midnight, and you’ve created a perfect storm.

Then you blame “work stress.”

Energy is earned the night before.

The Core Principles of Never Feeling Tired

Here’s the framework I use.

• Engineer your environment

• Remove stimulation before bed

• Control temperature and darkness

• Respect caffeine

• Use a shutdown ritual

• Train hard, even when tired

Now let’s unpack each.

Engineer Your Sleep Environment

Your brain runs on cues.

If your bed is associated with scrolling, bright light, and mental stimulation, it will not associate it with sleep.

So I removed the friction.

• My phone usually stays across the room.

• No doom-scrolling in bed.

• The only thing on my bedside table is a Kindle.

I read 10–20 minutes. Warm light. No notifications.
Eyes get heavy. I sleep.

That single change eliminated the “lying awake scrolling” problem.

I also try to use a physical alarm clock.

When you have to physically stand up to shut it off, snoozing becomes inconvenient.

Small environmental changes will always beat willpower.

Control Temperature, Darkness, and Noise

This is where most people leave performance on the table.

The ideal sleep temperature for most humans is around 18–19°C.

Your core body temperature drops when you fall asleep. If your room is too warm, your body struggles.

I sleep on an Eight Sleep Pod for precise temperature control. It adjusts throughout the night so I’m never overheating.

When I travel:

• Sleep mask if the room isn’t pitch black.

• Ear plugs if there’s noise.

• Curtains fully shut.

Darkness is not optional. Even small amounts of light reduce sleep depth.

If you can’t control the hotel environment, you control your tools.

Sleep mask + ear plugs = portable blackout system.

Respect Caffeine (Even If You Think You’re “Fine”)

Caffeine has a half-life of roughly 5–7 hours.

That means your 3 PM coffee is still active at 10 PM.

You may fall asleep, but your sleep quality still suffers.

My rule: no caffeine after 2 PM.

Before that? Fine.

After that? Decaf only.

This single boundary dramatically improves deep sleep consistency.

You don’t notice the damage immediately, but you’ll notice it in long-term fatigue accumulation.

Eat and Live Like Someone Who Wants Good Sleep

You cannot eat garbage and expect great recovery.

I prioritize:

• High-protein meals

• Whole foods

• Stable blood sugar

• Minimal ultra-processed junk

And I avoid eating too close to bed.

Large meals right before sleep force your body to digest when it should be recovering.

Light dinner. Protein-focused.
Finish eating at least 2–3 hours before bed when possible.

The Counterintuitive Rule: Push Through

This is important.

Sometimes you will feel tired.

Most people immediately:

• Skip the workout

• Stop deep work early

• “Rest” in unstructured ways

But here’s what I’ve noticed:

If I stay disciplined, train, work and eat clean, even when slightly tired, the following nights improve.

Your body responds to rhythm.

• Hard training → deeper sleep.

• Focused work → mental fatigue → easier sleep.

• Structured days → consistent circadian rhythm.

When you’re dialed in, sleep rewards you.

When you drift, sleep becomes chaotic.

Obviously, this doesn’t mean ignore real exhaustion or illness.

But mild tiredness? That can often be solved by a little bit of discipline and consistency.

The Compounding Effect of Sleep

This is the part most people underestimate.

Sleep compounds.

Good sleep tonight → better training tomorrow.
Better training → better sleep tomorrow night.
Better sleep → sharper thinking → better work.
Better work → reduced stress → better sleep.

It becomes a positive flywheel.

However, the opposite is also true.

One chaotic night turns into:

• More caffeine

• Worse sleep

• More stress

• Less discipline

And suddenly you’re “just tired all the time.”

Energy is a system.

What This Actually Looks Like in Practice

Here’s the minimal version:

• Phone outside reach.

• Kindle/Book instead of scrolling.

• No caffeine after 2 PM.

• Cool room (or temperature-controlled setup).

• Sleep mask + ear plugs when needed.

• Finish eating earlier.

• Train even on low-motivation days.

No hacks and no supplements required.

Just consistent inputs.

Sleep Is a Force Multiplier

You want:

• Better grades

• Better lifts

• Better health

• Better decisions

• Better mood

• Better relationships

Start with sleep.

Protect your sleep, and your waking hours will get better automatically.

And once you treat it that way, you stop asking “Why am I so tired?”, but start asking “What system did I break?”.

That’s essentially what Output Theory is about.

Optimize the input.
Multiply the output.

Thanks for reading!

See you next week
— Tobi

Something you should do.
Something you plan to do.
Something you usually don’t end up doing.

For me, it’s the opposite.

I’ve averaged well over 10,000 steps per day for the last ~3 years. Often closer to 12,000. And at this point, I don’t track it obsessively or plan walks into my calendar. It just… happens.

That didn’t come from motivation.
It came from systems.

Here are the habits that made daily steps effortless and automatic.

Why should you even care?

I genuinely believe that walking is one of the most underrated habits out there.

I even wrote a full blog post about the benefits of walking here:

So without any further ado, let’s get into the tips and tools that helped me the most.

1. Always Take the Stairs

At work. At home. At airports. At train stations.

Escalator or elevator is the default for most people.
Stairs became my default.

One stair decision barely matters.
Three or four per day compounds fast.

Over a month? Thousands of extra steps.
Over a year? A completely different baseline.

This works because:

• No extra time required

• No willpower once it’s habitual

• No “workout mindset” needed

It’s just choosing the slightly harder path, consistently.

2. Park Further Away (On Purpose)

Most people optimize for minimum walking.

I do the opposite.

When I drive somewhere—work, groceries, gym—I deliberately park further away.

This gives you three benefits at once:

• Forced walking, no negotiation

• 500–1,000+ extra steps with zero effort

• Easier parking (less circling, less stress)

You don’t notice it day to day.
You feel it over months.

3. Drink More Water (This One Is Sneaky)

This is an indirect step hack, but one of the most reliable.

More water → more bathroom trips → more standing up → more walking.

You break long sitting blocks automatically.
Your body moves without “deciding” to move.

Which brings me to the next layer.

4. Don’t Fill Your Bottle All the Way

I almost never fill my bottle completely.

Instead:

• I drink the same amount overall

• But I refill more often

That means:

• More trips to the kitchen

• More trips to the bathroom

• More excuses to stand up

And when I’m already up…

5. Use the Further Bathroom

If there’s a bathroom nearby and one a bit further away—even on another floor—I take the longer route.

This sounds stupidly small.
It’s not.

These “micro-walks” stack all day long, especially in office environments where people barely move.

6. Walk After Meals

A short walk after eating does two things:

• Improves blood sugar regulation

• Adds steps at a time where people usually sit

This doesn’t need to be a long walk.
5–10 minutes is enough.

Think of it as brushing your teeth for your metabolism.

I wrote more about why walking is so underrated in a separate issue, but the short version is this:

Walking is one of the highest ROI health habits there is.

7. Walk First Thing in the Morning

If you can do one intentional walk per day, make it a morning one.

Even a short walk:

• Resets mood

• Clears mental fog

• Starts the day without rush

It sets the tone.

Once you start the day moving, it’s much easier to keep moving.

8. The Nuclear Option: Walking Pad + Standing Desk

This was the thing that had the biggest impact for me.

A walking pad under a standing desk completely changes the game.

While working:

• Slow walking

• No impact on focus

• 2,000–4,000 steps per hour

When I use mine, I can hit my daily step goal before the workday is even over.

The Real Lesson

None of these tips are impressive on their own.

That’s the point.

Each one adds a small amount of movement.
Together, they change your baseline.

You stop asking:
“Did I walk enough today?”

And start living like someone who just… moves.

That’s how habits stick.
Not through effort, but through defaults.

Make movement unavoidable.
Make the good path frictionless.

And suddenly, 10,000 steps isn’t a goal anymore.
It’s just how your day works.

Thanks for reading!
— Tobi

💡 Question: What are some tricks you use to get more steps in?

Leave a comment

Everyone talks about posting more.
Writing better headlines.
Collaborating with other writers.

Those things work. But they’re also obvious. Which means everyone is doing them.

When everyone uses the same tactics, you’re competing for the same attention in the same way.

Real leverage comes from the boring, hidden, underused stuff.
The things sitting right inside Substack that most people ignore.

Here are the growth strategies that actually moved the needle for me, and that almost nobody talks about.

Read more

However, a surprising amount of it is wrong, or at least incomplete.

Over the years, I’ve noticed that the biggest productivity gains sometimes don’t come from new tools or fancy systems, but from unlearning myths I have blindly accepted.

Here are the ones that matter most.

Myth #1: Motivation leads to action

It’s actually the other way around.

Motivation is not a prerequisite. It’s a byproduct.

Small actions create small wins.
Small wins create momentum.
Momentum creates motivation.

Waiting to feel like it is the fastest way to stay stuck. Because motivation itself just comes and goes. You can’t rely on it.

Myth #2: Hustle culture is always bad

Burnout culture is bad.

Hard work isn’t.

If your goal is extraordinary, don’t get there by accident or with four casual hours per week.

Almost everyone who’s built something meaningful went through a period of intense effort first, then optimized for balance later.

The key question isn’t “Is hustle good or bad?”
I think the better question is:

What is my goal, and does my effort match it?

Myth #3: Productivity and self-care are opposites

They’re often the same thing.

Sometimes the most caring thing you can do for yourself is:

• finishing the task

• submitting the work

• meeting the deadline

Avoiding responsibility in the name of “self-care” often just delays stress—and multiplies it.

Personally, I feel like anxiety usually fades after having spent some good effort on a problem or task, and then in turn makes me feel better.

Real self-care reduces future pain.

Myth #4: Vague goals are enough

Abstract goals are fine, but incomplete.

Two upgrades matter:

1. Proximal goals
Goals closer in time create more motivation than distant, abstract ones.

“Lose 40 lbs by the end of the year” beats “Get a six-pack”

2. Intrinsic goals
Goals based on growth, skill, or contribution outperform external scorecards.

You control effort and learning.
You don’t control markets or algorithms.

Myth #5: You can do everything if you’re productive enough

You can’t.

Your to-do list will always be infinite.

Accepting finitude is freeing.

Once you admit you can only do three meaningful things today, the noise fades. And your focus sharpens.

Myth #6: “I don’t have time”

You do.
You’re choosing something else.

Having time is just a matter of priority.

Reframing matters:

“This isn’t a priority right now.”

That single sentence restores autonomy and makes you more likely to pursue your goals.

Myth #7: Productivity is about doing more

I would say it’s about doing more of the right things.

I like this equation:

Productivity = (Meaningful Output ÷ Time)

Speed without direction is useless.

What matters is how much of your desired outcomes you are able to achieve in what timeframe.

Myth #8: You need large blocks of time to do good work

You don’t.

Waiting for perfect conditions is how projects die.

Even allocating small slices of your time to a goal can produce meaningful output, especially when done consistently.

Also, in addition you will realize how often those “five minutes only” turn into muc more.

Myth #9: Your environment must be perfect

Helpful? Yes.
Required? No.

Candles, desk setups, morning routines: they’re preferences, not prerequisites.

The fewer conditions you need to start, the more you’ll actually finish.

Myth #10: Small optimizations don’t matter

They do.

When they reduce friction everywhere.

Typing faster.
Keyboard shortcuts.
System defaults.

When the gap between thinking and executing shrinks, output rises quietly but relentlessly.

Myth #11: Reading many books is useless

It depends why you’re reading.

Two modes:

• Exploration → breadth, context, curiosity

• Exploitation → depth, application, action

Skimming widely to explore is valuable, but I’d argue that slowing down to apply is essential.

Confusing the two is the mistake, not reading a lot.

The bottom line

Most productivity myths actually fail for the same reason:

They turn flexible tools into rigid rules.New ideas, once a week, in your inbox ✨

Real productivity is contextual. It’s not perfect. It’s human.

It’s less about hacks, and more about choosing better stories to tell yourself about effort, time, and progress.

And once you get those stories right, the output takes care of itself.

Thanks for reading!

See you next week
— Tobi

Not as an escape. Not as a random vacation.

But as a deliberate system reset.

This new change allows me to experience a completely new environment, and I think that such a change can bring a wide range of benefits.

Most people try to change themselves, but sometimes the smarter move is to change their surroundings.

Let’s break it down.

For years, we’re told the same story:

“If you really want change, you need more discipline.”

I actually think that’s backwards.

What seems like discipline from the outside, is often simply the result of a carefully crafted environment.

Here’s the core idea:

New beginnings don’t work because you’re inspired.

They work because your old scripts stop running.

When you get a new job, pursue new interests or move to a new city, something subtle but powerful happens:

Your brain loses its shortcuts.

And that creates a rare window where change is easy.

Environment beats willpower (every time)

Most behavior is context-dependent, not character-dependent.

Your brain runs on cues:

• Places

• Routes

• Sounds

• People

• Default options

At home, these cues are deeply wired.

You wake up → same phone grab → same breakfast → same commute → same gym → same people → same conversations → same habits.

Autopilot.

When you change your environment, you delete those cues.

There’s a temporary vacuum:

• Old shortcuts are gone

• Autopilot is disabled

• Conscious control comes back online

That’s why people can “accidentally” become:

• More disciplined

• More social (or more focused)

• More reflective

right after a move.

Identity resets when nobody knows you

At home, identity is sticky.

People remember you as:

• “the gym guy”

• “the one who’s always late”

• “that’s just how he is”

Those labels reinforce behavior—even when you want to change.

In a new environment:

• Nobody has expectations of you

• Nobody anchors you to old versions

• Nobody reinforces outdated identities

Because identity works like this:

repetition → self-image → habit reinforcement

In a new environment, you get to choose what you repeat.

That’s why environment change is one of the fastest ways to rewrite self-image.

Friction resets make habits negotiable again

In our usual environment, habits are often locked in by friction:

• Same grocery store

• Same commute

• Same food options

• Same gym

• Same routines

Everything is pre-decided.

With new surroundings:

• Nothing is automatic

• Everything requires conscious choice

You can:

• Design a better default day

• Remove low-ROI behaviors

• Build routines intentionally

This phase is rare and temporary.

Novelty accelerates learning

Your brain treats novelty as important.

Effects:

• Higher baseline attention

• Increased dopamine

• Stronger memory formation

That’s why days feel longer, you remember small details and learning suddenly feels easier.

This phase is very powerful, but does not last forever.

The goal is to install good systems before novelty fades.

Chosen discomfort multiplies growth

A new environment introduces:

• Mild loneliness

• Mild uncertainty

• Mild incompetence

This is the sweet spot.

Just enough friction to force adaptation.

And this adaptation builds new skills, emotional regulation and self-trust.

You learn:

• You can handle ambiguity

• You don’t need perfect conditions

• You’re more resilient than you thought

That confidence compounds.

The hidden benefit: optionality

After one successful change, you internalize a powerful idea:

“I can do this again.”

That belief:

• Reduces fear

• Increases leverage

• Makes you less hostage to circumstances

You stop treating locations, jobs, and routines as permanent.

Life becomes negotiable.

Bottom line

A drastic environment change works because it:

• Deletes old cues

• Loosens identity

• Improves signal

• Resets friction

• Accelerates learning

• Expands optionality

Often times, we don’t need more discipline.

We just need a new environment.

Thanks for reading!

— Tobi

Few people like talking about why they miss them.

Most goal advice sounds motivating, but motivation is a terrible long-term strategy. What actually moves the needle are a few boring, evidence-backed behaviors that quietly stack the odds in your favor.

Over the years, I discovered a lot of methods that drastically helpe me improve the odds of achieving the things I set out to do.

This issue is a step-by-step framework you can use to dramatically increase the probability that your 2026 goals actually happen.

At a high level, this framework does one thing really well:

It turns vague intentions into systems your brain can’t easily ignore.

And that matters, because the real difference between people who achieve their goals and people who don’t isn’t talent, intelligence, or ambition.

It’s whether their environment and habits force progress.

Let’s break it down.

Read more

Something you build to look good at the beach, fill out a T-shirt, or feel a bit more confident in photos.

I think that framing is incomplete. Muscle mass isn’t just an aesthetic upgrade.
It’s fundamental to being healthy.

Over the last 8 years of training consistently, I’ve become convinced of one thing:

Muscle is biological leverage.

Today, I want to show you why muscle mass quietly solves problems most people try to fix with supplements, diets, medications, or motivation hacks.

Let me explain.

Before we get started, let me make one thing clear: I’m not a doctor or a medical professional. Always consult your healthcare provider and do your own research. What I’m sharing here is based on my personal experience and the knowledge I’ve gathered over the years.

Here are the key points:

• Metabolism

• Correlation to Longevity

• Hormonal Stability

• Bone and Joint Protection

• Cardiovascular Health

• Energy Expenditure

• Cognition Upgrade

I’ve experienced all of these benefits myself over the past few years, after almost 10 years of training, many early mistakes, and roughly 20 kg (~44 lb) of muscle gained.

Let’s get into the details.

Metabolic health & glucose control

Your muscles are the primary place glucose goes after you eat.

Not your liver.
Not your fat tissue.
Your muscles.

More muscle means a larger sink for incoming energy. Think of it as a sponge.

When carbs hit your bloodstream, trained muscle pulls them in efficiently and stores them as glycogen instead of letting glucose linger and spike insulin.

That’s why, at the same diet, people with more muscle tend to have:

• Lower fasting glucose

• Lower HbA1c

• Better insulin sensitivity

• Fewer post-meal crashes

I like this analogy:

More muscle mass means a bigger battery.

If your battery is small, excess energy spills over and causes problems.
If your battery is large, it gets absorbed quietly.

That’s why muscle acts like a small insurance for when we eat too much food that spikes our blood sugar. It helps level those spikes out and makes them easier to handle.

Longevity & mortality

We’re obsessed with weight, BMI, and body fat percentages.

But when researchers look at who actually lives longer, something else stands out.

Strength.

Grip strength alone predicts all-cause mortality better than BMI. Low muscle mass and sarcopenia are among the strongest predictors of frailty, loss of independence, and early death.

This makes intuitive sense.

Life usually doesn’t kill you all at once. It chips away.

You fall.
You fracture.
You stop moving.
You lose independence.
Everything accelerates downhill.

Muscle slows that cascade.

More lean mass means:

• Higher resilience to illness

• Faster recovery from surgery

• Lower risk of falls and fall-related injuries

• Preserved independence decades longer

Joint Health & Protection

Some people actually avoid lifting because they’re afraid of “wear and tear.”

Ironically, the absence of muscle is what creates wear and tear.

Muscles are active stabilizers. They take load off passive structures like ligaments, cartilage, and discs. When muscles are weak, joints pay the price.

So strong muscles mean:

• Better joint alignment

• Lower shear forces

• Improved shock absorption

This is why properly trained lifters often have fewer chronic pain issues than sedentary people.

Your knees don’t fail because you used them.
They fail because they had to do the job muscles should’ve done.

Bone Density & Skeletal Strength

Bones respond to force.

Muscle contractions pull on bone, signaling it to remodel and strengthen. This is how bone mineral density is built and preserved.

Without that signal, bones quietly weaken.

That’s why resistance training is one of the most effective interventions against osteoporosis and fractures, especially with aging or calorie deficits.

Muscle loss often precedes bone loss.
Protect the muscle → protect the skeleton.

Hormonal Environment

Resistance training improves androgen receptor sensitivity.

It enhances growth hormone pulses. It improves leptin and ghrelin signaling, making hunger regulation more stable over time.

Chronic cortisol tends to come down, because your system becomes better at handling stress.

This is subtle but powerful.

Cardiovascular Health Is Not Cardio-Only

Cardio matters. Obviously.

But muscle improves cardiovascular health in less obvious ways.

• Improved blood pressure regulation

• Better endothelial function

• Improved lipid partitioning (less visceral fat storage)

• Higher VO₂ max when combined with cardio

When combined with cardio, strength training raises your ceiling. Better running economy. More power per step. Lower injury risk.

Essentially, s strong body makes the heart’s job easier.

Increased Energy Expenditure

This is where muscle really shines.

More muscle mass meaningfully increases your body’s total energy throughput:

• Higher resting energy expenditure

• Higher cost of movement (every step, rep, and task burns more)

• Higher recovery energy demand after training

The result:

• You can eat more and stay lean, or

• Lose fat on higher calories than someone with less muscle

Just as important: muscle increases activity tolerance.
You move more without trying. You fidget more. You train harder. You recover faster.
Daily energy burn goes up without conscious effort.

This is why muscular people often:

• Maintain leanness with ease

• Lose fat with less suffering

• “Get away with eating more”

More muscle = higher baseline output.
Higher output = easier fat loss, easier maintenance, more dietary flexibility.

Muscle Reduces Chronic Inflammation

Contracting muscle releases myokines with anti-inflammatory effects.

This lowers chronic low-grade inflammation, improves immune surveillance, and speeds up recovery from illness.

You get sick less often.
And when you do, you could recover faster.

Muscle Makes Daily Life Trivially Easier

This part is underrated.

Carrying groceries becomes a non-event.
Long days don’t drain you as much.
Posture improves without effort.
Back pain decreases.

Life tasks take up less of your available capacity.

That leaves more bandwidth for things that actually matter.

Muscle Improves Sleep

Resistance training improves sleep depth, sleep onset, and slow-wave sleep.

Muscle also acts as an evening glucose sink, reducing nighttime awakenings caused by blood sugar swings.

Better sleep feeds back into everything else.

The Bottom Line

Most people chase muscle for the least important reason.

Muscle is not just about aesthetics. It’s about health.

If you care about long-term health, performance, and resilience, you should do some form of resistance training.

It’s one of the highest-leverage investments you can make in your body.

Build muscle early.
Maintain it forever.

Everything else gets easier downstream.

That’s all for this week.

Thanks for reading :)
— Tobi

For me, What We Owe the Future by moral philosopher William MacAskill did exactly that.

MacAskill is one of the people behind the Effective Altruism movement — a philosophy built on a simple idea: use evidence and reason to do as much good as possible.

This book shifted something in me. It changed how I think about meaning, responsibility, and what it actually means to live a good life.

And it starts with one radical idea:

Most of the people we can positively impact aren’t alive yet.

Today, I want to break down the ideas from the book that hit me the hardest; ideas that completely change the way you think about your time, your career, and the choices you make.

Here’s the roadmap:

1. The future is unimaginably big

2. Future people matter.

3. We might be living at the most influential moment in human history.

4. What you do actually matters far more than you think.

Let’s dive in.

1. The Future Is Big — Really Big

And the people who will live in it matter just as much as you do.

Humans have been around for ~300,000 years. Agriculture appeared only 10,000 years ago. Civilization? Even more recent.

If humans last as long as a typical mammalian species (roughly 1,000,000 years) then we are still in the first 1% of our entire story.

And unlike other species, we’re not constrained by biological limits. We build tools. We reason. We collaborate. Our potential timeline isn’t measured in thousands of years, but millions.

Here’s the point MacAskill makes:

99% of all humans who will ever exist haven’t been born yet.

And their lives, their happiness, their safety, their opportunities, depend on the decisions we make today.

This isn’t just philosophy. It’s moral common sense.

Imagine you could prevent a genocide that would kill one million people. Now imagine that genocide happens 100 years from now. Or 1,000. Or 2,000.

Is it suddenly less important? Less tragic?
Of course not.

Time doesn’t diminish moral worth.

And if future people have the same moral weight as present people, then — statistically — almost all moral weight lies ahead of us.

That insight alone reshapes your worldview.

But things get even more interesting.

2. We Are Living at One of the Most Important Times in Human History

And not because everything is amazing, but because everything is fragile.

Look at the graph of global output across history. It’s basically flat… until you hit the Industrial Revolution. Then it explodes vertically.

The last 250 years have been an anomaly:
• exponential technological progress
• exponential population growth
• exponential increases in our ability to shape (and damage) the world

And with each breakthrough, our leverage increases.

Nuclear weapons made human extinction possible.
Engineered pathogens could, in theory, be far worse.
Artificial intelligence is developing so fast that even experts disagree on whether we’re headed toward utopia or catastrophe.

Here’s the uncomfortable truth MacAskill explains:

For the first time in history, a single individual — not a nation, not an army, a single person — may soon have the ability to cause global harm.

You don’t need an imagination to see the danger. Humans snap and have bad days. If even 0.0001% of people are unhinged… that’s still thousands of people with access to increasingly powerful tools.

We’re living in the era where our technological capacity has outpaced our maturity.

This is why “longtermist” argue that right now is unusually critical:
We’re powerful enough to destroy ourselves… but not yet wise enough to guarantee that we won’t.

But it’s not all doom.

Because unlike past generations, we can actually do something about it.

3. You Can Meaningfully Improve the Long-Term Future

And the things that matter most aren’t sci-fi fantasies — they’re real, practical problems.

MacAskill’s message is not “panic. It’s “prepare.”

Think of humanity as setting off on a risky expedition. The path ahead is uncertain, and the terrain is unknown. But you can choose what equipment you carry.

Here are the things individuals actually can do:

A. Choose a career that reduces existential risk

Some fields are insanely impactful because they influence whether civilization continues to thrive:

• AI safety — making sure advanced AI is aligned with human values
• Biosecurity — preventing engineered pandemics
• Nuclear risk reduction
• Climate stability
• Global governance & policy

MacAskill points out something staggering:

In 2020, around 40,000 people were working to make AI more powerful.
But only about 300 were working to make AI safer.

Some fields don’t just need more smart people. They need them urgently.

If you’re a software engineer, mathematician, biologist, researcher, doctor, or someone who wants their career to matter: this is the frontier.

(And if you want clarity on what paths truly make an impact, 80,000 Hours is an incredible and free resource.)

B. Donate effectively

This is a finding that took me personally quite by surprise.

The gap between average charities and the most effective ones isn’t 2x or 5x.

It’s often 100x or 1,000x.

Pandemic prevention vs. counter-terrorism is a perfect example:
• Pandemics kill massively more people.
• Pandemic prevention receives a fraction of the funding.

If you have disposable income, directing even a small portion of it toward high-impact causes compounds far beyond your lifetime.

C. Spread good ideas

Movements start with individuals.
Norms change because people talk.

You don’t have to become a philosopher.
You don’t have to become an activist.

You just have to understand the stakes and share them with clarity.

Even writing this newsletter could be part of that ripple effect.

Why This Book Changed Me

Before reading it, I thought about my impact mostly in present-tense terms:

• improving my own life
• helping people today
• building things that matter now

But MacAskill forced me to zoom out drastically.

If almost everyone who will ever live is in the future…
If we currently have huge leverage to influence that future…
And if individual choices actually scale through careers, donations, norms, and innovation…

Then the conclusion is simple:

We are early in the human story, and what we choose to do now echoes through centuries.

This is both a responsibility and a privilege.

You and I are alive at a moment when our actions matter far more than they would have in most previous eras. That’s rare. And it means we should take our choices seriously.

Not in a stressed-out sense, but in the sense that our lives can genuinely make a difference.

Final Thoughts

If any of this resonates, read the book. It’s one of the most important pieces of thinking I’ve encountered.

It could change the questions you ask about your life.

And often, that’s all you need to shift your trajectory.

Because once you start seeing yourself as part of a story that stretches thousands, maybe millions of years into the future…

You stop asking “What do I want right now?”
And start asking:

“What can I do that will matter for the people who come after me?”

That’s a powerful frame to live by.

See you next week.
— Tobi

But the deeper truth is this:

Every writer grows in curves. And every curve ends in a plateau.

If you don’t understand the plateaus, you’ll misdiagnose your current stagnation. You’ll think you need “more effort” when what you really need is a different kind of effort.

You’ll grind harder on the wrong thing. You’ll stay stuck.

I’ve gone through each of these curves myself while growing Output Theory from 0 to thousands of readers in a few months. My trajectory wasn’t smooth at all. It was a staircase.

Each jump only happened when I switched leverage types.

Today’s newsletter is the guide I wish I had earlier:
The four growth plateaus, the behavior that breaks each one, and how you can move to the next curve on purpose.

Plateau 1 — The Silent Stage

Read more

“Practice speaking.”
“Memorize conjugation rules.”
“Do lots of grammar drills.”

It sounds logical. It also happens to be wrong.

In this post, I will go into why it is wrong, while showing you the mechanism that actually drives language acquisition.

I’ve built up a lot of experience here, since Japanese is the fourth language I’m learning after German, Italian, and English. And this time, with Japanese I’ve approached language learning in a really structured, research-driven way by studying language acquisition theory.

I truly believe that by applying these principles, language learning becomes 10x more effective. It will also explain why so many people grind for years and still can’t hold a simple conversation.

The bold truth: You don’t learn languages by speaking. You learn them by understanding messages.

That’s the core of Stephen Krashen’s research on language acquisition — decades of study, countless experiments, all pointing to one simple mechanism:

Humans acquire language only when they receive messages they understand — “comprehensible input.”

Not through memorization.
Not through grammar drills.
Not through speaking practice.

Understanding → Acquisition.
Everything else is optional or supportive.

Here are the key insights this unlocks:

1. Your brain is a pattern-recognition machine, not a grammar computer

Think about how you learned your mother tongue.

Did anyone hand you grammar worksheets at age two? Did you drill conjugations? Did your parents give you flashcards?

Obviously not.

You learned because you were surrounded by messages you could understand. Your brain extracted patterns automatically:

– Word order
– Meaning from context
– Pronunciation
– Grammar rules (without ever being taught them explicitly)

For example, English speakers know “the big red ball” sounds natural and “the red big ball” doesn’t. Almost no one can explain the rule. But they know it.

Why?
Because input created intuition.

Once you see that, traditional language learning looks a bit… backwards.

2. Speaking doesn’t cause learning — it reveals learning

This idea alone pisses off half the language-learning world.

But it’s true.

Speaking is output. Output is a byproduct of acquisition, not the cause of it.

Krashen’s research found:

– Speaking doesn’t build mental representations of a language.
– Speaking doesn’t improve grammar acquisition.
– Speaking only improves when comprehension improves.

This matches real-world experience.

When I started learning Japanese in April, I spent six months doing zero speaking. Not one conversation. No voice chats. No tutors. Nothing.

Just input + structured vocabulary building to make that input comprehensible.

Then I went to Japan.

And suddenly… Japanese came out. Naturally. Automatically. Without freezing. Without thinking about grammar. Without fear.

People even complimented my pronunciation.

Not because I practiced speaking — but because I’d built a huge reservoir of patterns through input.

3. Grammar drills give you knowledge — but not ability

You can study grammar rules for 500 hours and still fail to understand native speakers talking at a normal pace.

Grammar knowledge is like knowing the physics of swimming.
Input is like being thrown into the pool with a float.

Only one actually makes you a swimmer.

Grammar isn’t useless: it helps notice patterns in the input. But you cannot build fluency from grammar rules alone.

4. Active study is useful — but only to boost your input

Active learning can be extremely helpful, but only when used correctly.

Flashcards.
Vocabulary lists.
Basic grammar explanations.

Their purpose is simple:

Give you enough vocabulary and understanding so that native input becomes comprehensible.

Especially for hard languages like Japanese, learning 1,000–2,000 words early accelerates everything else.

But the real acquisition happens from:

– Native TV shows
– Books
– YouTube
– Podcasts
– Conversations
– Slice-of-life content
– Immersion with things you enjoy

A personal example

I grew up learning English mainly through input: YouTube, TV shows, movies, books.

School didn’t make me fluent.
The internet did.

Hours and hours of meaningful, interesting input. That’s what gave me—and millions of other Europeans—native-like intuition in English, even without living abroad.

This alone should make us question why we treat every other language differently.

5. You must learn to be comfortable not understanding everything

Beginners often pause every three seconds to look up a word.
That kills the entire mechanism.

Input only works when it flows.

You should understand enough to follow what’s happening — not every single sentence.

Your job is to tolerate ambiguity.

The more input you consume, even imperfectly, the faster the fog lifts.

Takeaways

– You acquire language through input, not by speaking.
– Your brain builds intuition from patterns, not rules.
– Speaking emerges naturally when comprehension is strong.
– Grammar helps noticing, not acquiring.
– Active study is a help, not the main driver.
– Comprehensible input is the engine.
– Embrace ambiguity and keep the input flowing.

The bottom line

If you want to learn a language 10× faster, stop obsessing over speaking, memorizing, and drilling rules. Those feel productive but move you forward slowly.

Instead, build your entire strategy around this question:

“How can I maximize the amount of comprehensible input I get each day?”

If you do that for six months straight, you’ll experience a strange moment:

You’ll open your mouth… and the language will simply come out.

Not perfectly.
Not fluently.
But naturally.. and shockingly effortlessly.

That’s the power of real language acquisition.

Thanks for reading :)

Until next time.
— Tobi

💡 Question: What has helped you learning a new language?

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Stocks. Bonds. Index funds. Crypto. ETFs. Fine art. Watches. Futures.
And then the YouTube gurus telling you they make €3,000 a day trading forex from a beach in Bali.

No wonder people feel overwhelmed.
And underneath that overwhelm sits a deeper fear:

“What if I lose the money it took me years to save?”

That fear is rational.
But the solution is not to avoid investing.

The solution is to understand it.

What follows is the guide I wish everyone had when they start.
Just four simple ideas that will give you a solid, calm, long-term foundation:

— Own assets
— Think long term
— Let compounding do the heavy lifting

Everything else is noise.

Let’s break it down.

1. The Philosophy: Why Invest at All?

Investing is simply this:

Using today’s money to buy something that gives you more money tomorrow.

It’s necessary to fight against the enemy most people underestimate: inflation.

Your €1,000 today buys a laptop.
But in five years, that same laptop might cost €1,300.

If your money just sat in a bank account, it lost buying power.

Investing protects you from that.

And more importantly:

Investing lets your money work while you sleep.
(Not metaphorically, but literally.)

This is the “eighth wonder of the world” effect Albert Einstein talked about: compound interest, the same principle I broke down in detail in my money psychology newsletter .

The earlier you start, even with tiny amounts, the more the curve bends in your favor.

2. Why Stocks? And Why Index Funds?

Technically you can invest in anything:

• Real estate

• Government bonds

• Crypto

• Fine art

• Watches

• NFTs

• Single-company stocks

But here’s the reality:

Many of those require:
— deep expertise
— huge amounts of capital
— high risk tolerance
— or all three at once.

That’s why the wealth-building vehicle for most people is:

Index funds.

Instead of betting on one company (Apple, Tesla, Netflix), you buy a tiny slice of hundreds of companies at once.

The S&P 500 index is the classic example:
500 of the biggest companies in the U.S., weighted by size.

When you put €1,000 into an S&P 500 index, you aren’t choosing winners.

You’re betting on human productivity.

And productivity tends to go up.

This is exactly why long-term investors like Warren Buffett tell regular people:

“Don’t pick stocks. Just buy the S&P 500 consistently.”

And it’s also why in my personal finance newsletter I emphasize:
“Volatility isn’t risk.”

Risk is probability of permanent loss. Volatility is just the market having mood swings.

If you don’t sell during downturns, you don’t lose.

Which brings us to the one fear that holds everyone back…

3. “What if I lose all my money?”

Here’s the truth:

If you invest in a single stock, yes — it could go to zero.

If you invest in crypto, it could go to zero.

If you invest in the 500 largest companies in the U.S., all going to zero at the same time…

…we have bigger problems than your portfolio.
(As in: societal collapse.)

Historically, the S&P 500 has been through:

• World wars

• Oil crises

• Inflation waves

• Recessions

• Market crashes

• Pandemics

• Tech bubbles

• Housing bubbles

And still, over long periods, it recovers and rises.

Why?

Because every day, millions of smart people across the biggest companies in the world are waking up, building things, selling products, delivering services, improving processes.

Value is constantly being created.

This is the single strongest argument for long-term index investing:
Human progress is the underlying engine.

That doesn’t mean you’ll never see red numbers.
You will.

But volatility ≠ danger.
Volatility = discounted prices.

(This is something I try to repeat across all my finance writing: downturns are sales, not disasters .)

So what should a complete beginner actually do?

Here’s the cleanest, most beginner-friendly roadmap:

Step 1 — Open a reputable brokerage account.

Whatever the equivalent is in your country. I like Interactive Brokers.

Step 2 — Buy a broad index fund.

Examples:
— S&P 500
— FTSE Global All Cap
— MSCI World

Step 3 — Automate a monthly contribution.

Even €25/month is better than nothing.

Step 4 — Do not touch it.

No panic selling.
No emotional decisions.
No timing the market.

Step 5 — Focus your energy on increasing income.

Your savings rate matters more than your stock picks.

Step 6 — Hold for decades.

Let compounding do the work.

This is exactly the same long-term mindset I shared in Naval Ravikant’s principles:
— play long-term games
— with long-term people
— using long-term assets

Do this, and you’ll outperform 95% of people — without ever “trying to beat the market.”

Final Thoughts

Investing isn’t about being smart.
It’s about being consistent.

It’s about understanding human progress, not predicting it.

Most importantly:

It’s about giving your future self a life with more freedom, not more stress.

If you want to build wealth without losing your sanity, this is the path.
Simple. Boring. Reliable.

And boring is underrated.

Because boring compounds.

Thanks for reading!

See you next Saturday
— Tobi

💡 Question: Which of these principles would you like to see me dive deeper into?

Leave a comment

Learning how to learn effectively is what allowed me to manage full-time software engineering, a full-time CS degree, fitness, Japanese learning, writing a weekly newsletter, and building digital products, all without burning out.

And once you understand the mechanics of learning, everything in life becomes easier. University becomes manageable. Languages become fun. Difficult technical topics stop feeling like walls and start feeling like puzzles.

Today I want to break down the exact principles I use. The same ones that let me:

• stay top of my CS class

• pick up technical systems at work rapidly

• learn Japanese consistently as a fourth language

• move quickly into new domains like fitness science, writing, finance, and more

These aren’t theories. They’re systems I rely on every single day.

Let’s get into it.

1. Sharpen the Axe: Meta-Learning First

If you gave me six hours to learn something new, I’d spend the first hour understanding how the subject works, how people actually master it, and which methods produce outsized results.

Most people skip this step. They just start grinding.

This is the equivalent of chopping wood with a dull blade.

When I entered university while working full-time, I quickly realized this wasn’t sustainable unless I built systems. So I stepped back and studied:

• how memory really works

• how spaced repetition compounds

• why active recall outperforms passive review

• how to structure deep-work sprints

• how to make learning frictionless

That foundation paid off immediately. My learning curve flattened. Hard topics stopped feeling chaotic and started feeling solvable.

This principle also shaped everything from my CS coursework to my commute systems (where I use train time for Anki and Japanese immersion) in posts like Stop Wasting Your Commute .

Sharpen the axe first. It saves hundreds of hours later.

2. Remove Friction, Not Add Motivation

Learning is less about “trying harder” and more about “removing resistance.”

A few examples:

• Physical timer → instant focus

Turning a 30-minute study sprint into a ritual makes the task non-negotiable.

• Japanese only for entertainment

Contextual rules: if I watch TV, it must be in Japanese. That turns entertainment time into immersion.

• Apps on my home screen:

Anki > Instagram. Audible > TikTok.

• Train = study zone, car = audio learning

This simple rule alone gave me ~500 hours of extra learning per year .

Once your environment aligns with your goals, learning stops being a fight. It becomes automatic.

3. Immerse Yourself in the Arena

You learn fastest when you operate in the environment where the skill actually lives.

For Japanese, immersion isn’t optional. It’s the fuel.

For coding, you learn fastest by building.

For communication, you improve by speaking, not theorizing about speaking.

When I started Japanese, I didn’t just memorize vocab. I threw myself into:

• listening immersion during commutes

• reading signs, menus, NHK Easy News

Immersion is uncomfortable — it exposes your weaknesses instantly.

That’s the point.

Every time I learned a new system at work, I asked senior developers to walk me through real code and production logic. Straight into the arena.

4. Attack Your Weak Links First

One of the fastest ways to accelerate learning is brutally simple:

Find your weakest point and drill it.

This is uncomfortable. It feels inefficient.

But it compresses months of progress into days.

When I started my CS degree, I noticed early the courses and topics that were the hardest. So instead of “warming up” with topics I already understood, I spent entire sessions attacking the exact concepts I was struggling with.

Same with Japanese: I struggled with listening. So I doubled down on listening immersion instead of escaping into grammar videos.

Weakness → spotlight → drill → strength.

Repeat.

5. Test Yourself Relentlessly (Active Recall)

If I had to choose one learning technique for the rest of my life, it would be active recall.

You don’t learn by reviewing.

You learn by retrieving.

This is the engine behind my entire Japanese routine, my university studying, and how I onboard new tech quickly at work.

Anki is my daily ritual. It’s the backbone of my memory system.

Test → fail → test → succeed.

That’s how memory works.

6. Seek Fast Feedback Loops

Feedback is the accelerant of mastery.

When I mentor junior developers at work, the difference between someone who learns quickly vs. slowly is usually simple:

How quickly they expose their work to correction.

For Japanese, this means writing sentences that native speakers correct.

For coding, this means sending merge requests early instead of hiding drafts for weeks.

For fitness, it’s why I film my lifts repeatedly to adjust form.

Fast feedback = fast progress.

Slow feedback = slow progress.

7. Space It Out: Let Your Brain Breathe

Learning is biological.

Your brain needs time to consolidate.

Cramming creates illusions of understanding. Spacing creates actual understanding.

This is why my Japanese routine is spread across:

• morning vocab repetition

• afternoon immersion

• evening reading or grammar

• weekend long sessions

The same thing applied during my most intense exam periods: spacing turned overwhelming subjects into manageable chunks.

Spaced repetition is the backbone of long-term retention.

8. Teach What You Learn — Immediately

Nothing clarifies your thinking like trying to explain it.

This newsletter is one giant feedback loop for my own learning. Writing forces me to:

• simplify

• find clarity

• remove contradictions

• understand at a structural level

When I write about personal finance, productivity, psychology, or fitness, I’m not teaching from a pedestal. I’m rather reinforcing my own learning, similar to what I described in 5 Ideas From Naval .

Teaching makes everything stick.

If you want to learn fast, teach early. Teach often. Teach imperfectly.

The Real Reason I Can Talk About This

My journey — combining full-time work, full-time university, language learning, fitness, content creation— forced me to drastically improve the mechanics behind learning.

I had to become efficient.

I had to create systems.

I had to iterate fast.

I had to make learning fit a life, not replace one.

And if there’s one thing I’ve realized, it’s this:

Anyone can learn fast if they learn intentionally.

Learning is a skill.

And a skill can be trained.

Final Thoughts

If you want to learn anything faster, focus on this:

• Sharpen the axe

• Remove friction

• Immerse yourself

• Attack weaknesses

• Use active recall

• Seek fast feedback

• Understand deeply

• Space it out

• Teach early

And above all:

Don’t make learning harder than it needs to be.

Design your system, then trust it.

That’s how you learn faster — in university, at work, in languages, in fitness, in life.

Thanks for reading!

See you next Saturday

— Tobi

Nobody knows you. Nobody cares. You hit publish and… silence.
This is the part where most people quit.

But in June, I made a decision: I’d publish one high-quality issue of Output Theory every single week — no matter what.

Five months later, we passed 5,000 subscribers and landed in the top ~5% of fastest-growing newsletters on Substack.

Today I’ll break down the exact levers I pulled and the ones that actually mattered.

What This Journey Taught Me

When I launched Output Theory in June, I had no online audience, no social media following, and no prior experience in newsletter publishing.

My subscriber count was a flat zero. Today, just five months later, Output Theory is sitting well over 5,000 subscribers and is recognized as one of the fastest-growing publications in its niche.

No audience. No ads. No hacks.

What follows is the playbook I wish someone had handed me on day one.

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