Do you want your coins to bring you 10x, 20x, 30x? So why are you nervous about a 20% drop?
As long as the coins are with you, you haven't lost: you lost when you sold for less than you bought.
Warren Buffett has held shares of some companies for more than 20 years. Take an example from him.
The only caveat: never buy garbage at a speculative pump, and at a dump either.