I've been involved in investing for 10 years

Because I didn't know how to cut losses, I went to zero twice
But later I studied deeply and practiced a wave of stop-losses, and although I didn't lose much, I also couldn't make money
In the end, I finally understood:
💥The true meaning of stop-loss is: logical stop-loss; not: loss percentage stop-loss!
Stop-loss should depend on whether your original buying logic still holds; if it doesn't, no matter how much you are losing at the moment, you should decisively exit! And not just set a simple, blunt stop-loss line, and exit once the loss reaches a preset ratio.
For example, I previously lost heavily in blockchain games; according to this stop-loss logic, once I find that the blockchain game track is no longer viable, I should immediately stop-loss, regardless of whether I was losing 1% or 99% at the time! Instead of gambling on whether a certain project team will continue to manipulate or pull something. Because I initially entered because I was optimistic about the blockchain game track, when that logic is no longer valid, I need to exit immediately!
Here's another example opposite to the above: if you are now long-term optimistic about the AI track and have bought leading AI stocks, planning to do value investing. If later, the three giants go public, causing the US stock market to crash, and you lose more than 30%, you still shouldn't stop-loss, because your buying logic isn't about swing trading; as long as your logic for investing in AI remains, you should continue holding!
Another benefit of this stop-loss mindset is that it forces you to think more carefully about your buying logic before entering.
Of course, there is a special case: if you buy based on candlestick technical analysis and set your stop-loss according to the technical analysis, that is perfectly fine and not contradictory!