It really depends on all the information you have on that particular coin. If I think a massive sell of will happen, and that price is probably a good one, and I will sell it. If in a later time I think it will go up again, I will just buy the dip, and I'm making profit. If I think there is no reason for the price to go down, and it's the market doing it's normal cycles, then I will just hold it. For instance, bitcoin price is dropping a lot these days, and I sold a few at $14k, I am now waiting for an opportunity to buy them back again.