Lessons

For years, growth feels underwhelming — you're mostly just adding your own money. Then returns start earning returns on returns, and the curve bends upward almost out of nowhere. The point isn't to expect fireworks early; it's to survive long enough to reach the steep part. Most people quit in the flat years, right before it gets good.

Takeaway: Time in the game beats cleverness. The magic is nearly all at the end.

Up 50%, then down 50%, and you're not flat — you're down 25%. Big swings drag on what you actually keep, even when the average looks fine. Two strategies with the same average return can finish miles apart if one is bumpier than the other.

Takeaway: Chasing higher returns usually buys more volatility too — and volatility quietly eats the gains.

Lose half your money and you need to double what's left just to get back to even. The deeper the hole, the more absurd the climb — a −80% fall needs a +400% gain. This is why avoiding big drawdowns matters more than catching big winners.

Takeaway: Protecting the downside isn't caution — it's arithmetic.

Being right often feels good, but it doesn't pay the bills on its own — the size of your wins versus losses matters just as much. A system that wins 35% of the time with big winners can beat one that wins 70% with tiny ones. What counts is expectancy: win rate and size together.

Takeaway: Don't chase a high win rate. Chase positive expectancy.

Bet too big and a normal losing streak — which always arrives eventually — can dig a hole too deep to climb out of, before your edge ever pays off. Professionals bet small not because they doubt themselves, but because they want to still be here when the edge shows up.

Takeaway: The first job isn't to win. It's to not go broke.

Try enough strategies on past data and one will look brilliant by pure luck — even in a market with no edge at all. A gorgeous historical curve is the easiest thing in the world to produce and the least meaningful. The only real test is data the strategy never got to see.

Takeaway: Be most suspicious of the things that look perfect on the past.

Take the exact same set of yearly returns and shuffle the order — if you're steadily paying money in, you do not end up in the same place. Counter-intuitively, getting the bad years first can leave you richer, because you buy more while prices are low. Order isn't just noise; it shapes the outcome.

Takeaway: An early crash, while you're still adding money, can be a gift.

A few pounds a trade feels like nothing — but it's charged on every trade, it never has a losing day, and what matters is its size next to what each trade makes. A big edge shrugs it off; a thin one gets eaten alive. For active traders, costs are often the biggest position they hold.

Takeaway: It's not the size of the cost — it's the cost versus your profit per trade.

Over a small number of trades, a lucky gambler and a skilled trader are indistinguishable — both can show a lovely run. You need a real sample before results mean anything. Mistaking a hot streak for an edge is one of the most expensive errors in trading.

Takeaway: Small samples fool everyone. Always ask: "could luck alone have done this?"

More trading means more costs, more chances to be tempted into a bad decision, and more of your edge handed to the spread. Slowing down — fewer, better trades — cuts costs and mistakes at the same time, without needing a cleverer strategy. It's the rare improvement that's free.

Takeaway: When in doubt, do less. It usually keeps more.