If you could only keep one mental model, keep compounding.
Not the financial kind — although that’s where most people learn the word. The general kind: small things that build on each other over time, where each unit of input produces more output than the last.
It Applies Everywhere
Skills. Learning one thing makes the next thing easier. Not linearly — exponentially. The person who understands statistics, programming, and business doesn’t have three skills. They have a superpower that none of those skills produce alone.
Reputation. Every honest interaction builds trust. Every kept promise makes the next one more believable. This compounds so slowly that most people don’t notice — until they need a favour and discover they’ve been building credit for years.
Writing. The first post is terrible. The tenth is okay. The fiftieth is good — not because you studied writing, but because each post taught you something the previous one couldn’t. Voice, frameworks, audience — all compounding simultaneously.
Tools. Every system you build makes the next one faster. The pipeline you built last month becomes the foundation for this month’s project. The naming convention you chose becomes an identity.
The Filter
If compounding is the model, then the decision framework writes itself: does this compound?
A job that builds transferable skills compounds. A job that pays well but teaches nothing doesn’t.
An honest relationship compounds trust. A transactional one doesn’t.
Deep thinking compounds into better judgment. Organising your organisation doesn’t.
Writing publicly compounds — audience, ideas, reputation, all at once. Writing in private notebooks doesn’t, or at least compounds much more slowly.
The Trap
The trap is confusing activity with compounding. Not everything that feels productive actually builds on itself. Some work is linear: you do it, it’s done, nothing carries forward. Meetings. Most emails. Administrative tasks. They consume time without producing compound returns.
The discipline is asking, regularly: of everything I’m doing, what actually compounds? Then do more of that and less of everything else.
The Uncomfortable Corollary
If compounding works for good things, it works for bad things too. Bad habits compound. Distrust compounds. Technical debt compounds. Small lies compound into a reputation you can’t escape.
The model doesn’t care about your intentions. It just multiplies whatever you feed it.
Choose carefully what you compound.