Holding is very good, if you hold the right coin. The most important thing to be patient and wait, and after a certain time the coin you hold will give you more profit than if you sell it all at once.
And how do you know that you hold the correct coin? If we are talking about Bitcoin or Ethereum, then in any case they will grow in value. And what about the rest of the coins and altcoins? How to decide which ones to sell at any price, and which ones to leave?