Personally, if the market is going up and I feel it is profitable, then I will sell it, so I can't really stick to when the time is right to sell or buy it. it all depends on the conditions of the crypto market itself. Usually, when the market is down like this it will take quite a while to recover, so this is a good time to buy a coin at a low price and hold it. if you are asked if you regret it or not when you pass a good moment to sell or buy, then it is already a risk, therefore we have to think about it and analyze it carefully first. not that I never regret it, but it will be better if we focus on the next trade or strategy.
Sticking to one specific price target can be boring because we usually aim for a high amount and that doesn't come too easy but if we don't set such a thing, we are free to sell whenever we like. Seeing small profits on your hand can make you feel more motivated to go for more, the same thing when buying but one cant tell when will the price recover. The price can recover maybe later or the next day who knows? So, don't be confident with yourself too much.
What makes you think having regret is a risk? I think this is normal if we talk about good moments because they are rare but you still missed them, what a shame but we can learn from this and not repeat the same thing.