We need to accept the facts that it's very difficult now to see a coins doing x10 x20 or even doing 50% returns on investment in this bear period. And nobody knows when the bulls will come. Therefore, it's will be advisable to exist when your coins do 20% returns or even less. I know some investors will not be satisfied with 20% but we need to be objective and understand this bear period will last longer than expect.
This is only applicable for newbies and not for long time holders. Since you cannot predict the market it is still use best to hold as long as you bought your coin at a very low price. For example if I bought my coins last 2015 there is no need to panic since I know this bear market will be over soon.