You can win 60% of your trades and still lose everything. Not because your entries were bad — because your position size was.

Here's the cleanest way I know to see it. Forget the market. One coin, $100. It lands heads 55% of the time — a real edge, better than almost anything in the actual market. The only question is how much of your stack you bet each flip.

Go all in? One tail and you're at zero — and over a long run, a tail is a certainty, not a maybe. Bet half? Win one, lose one and you go $100 → $150 → $75. You were right half the time on a coin you were favored on and you're still down 25%. That's volatility drag — swings don't cancel, they compound against you.

Now bet 5%. No single flip can hurt you, so your edge finally has room to show up, and the account grinds upward. Same coin. Same edge. Only the size changed — and it flipped certain ruin into steady compounding.

That's the whole lesson: your edge decides direction, but your size decides whether you're alive to collect it. And the recovery math is brutal — lose 50% and you need 100% just to break even. Small sizing keeps a bad streak a dent, not a grave.

What a disciplined trader does: decide size before the entry. Fix the dollars at risk per trade — a set fraction of the account — and let that dictate contract count. Cap total risk across correlated positions (five SPY longs is one big bet). And never size up because you feel sure. Conviction is the feeling that walks you off the cliff.

This is educational commentary, not personalized financial advice — but it's the number I'd check before every trade.

The full walkthrough, with the risk-of-ruin curve and the simulation on screen, is here: https://youtu.be/2awD47_EEGU

Size small, stay in the game.