There are two red lines in trading that you must never cross:
The first line: You must never let a small loss turn into a big loss. A small loss is a trading cost, making mistakes is normal, but a big loss is fatal. You must learn to control losses and avoid one trade from crashing your account directly; otherwise, you won't have a chance to recover.
The second line: You must never let a big profit turn into a loss. Simply put, don't let a cooked duck fly away. How many opportunities for big profits are there? Maybe just once a month. If you've made a big profit but didn't protect it well, and the profit retraced significantly, then you essentially worked for nothing. Suppose your win rate is 50%, and the other four times you only made small profits or broke even; you have to rely on this big profit to cover your losses. Protecting your profits is the only way to allow your account curve to spiral upwards, gradually recovering from losses. Do you understand?