Let me tell you about a mistake I made last month that cost me real money but taught me more than any winning trade.
Found a setup that looked perfect. Altcoin breaking resistance, volume increasing, all my indicators aligned. Felt so confident I went in with 15% of my portfolio. Way bigger than my usual 3-5% position size.
First two days: up 12%. Felt like a genius. Started planning what to do with profits.
Day three: regulatory news I didn’t see coming. My altcoin dropped 25% in hours. Suddenly my 15% position was down significant money. Not just percentage points, actual dollars that hurt.
The emotional damage was worse than the financial loss. Couldn’t sleep. Kept checking charts. Made revenge trades trying to make it back. Lost more.
What I learned: position sizing isn’t about missing gains, it’s about surviving losses. If I’d used my normal 3-5% rule, that same 25% drop would have been annoying but manageable. Instead it messed up my whole psychology for weeks.
Now I follow my rules regardless of conviction. Because even when you’re “sure,” the market can surprise you. And staying in the game long term matters more than any single trade.
Anyone else learned position sizing the hard way?