Cryptocurrencies have both bullish and bearish trends. Where during a bullish trend we can hold and sell when it reaches the top. But when Bearish starts to appear, we have to sell immediately, we even have to set up a sales system with the OCO system on Binance, if you use Binance.
And the problem is that not everyone can know when and at what price the peak of the bullish event occurred, because if this could be very easy to know, then everyone would be ready for it, and vice versa when the bearish trend came, for those who had time to sell more the beginning is ok, but for those who sell it late, they definitely have to wait for the bullish trend to come again, or use other capital to buy coins at the lowest price in bearish conditions.