Not all your life, of course, but what you can never do is sell in a panic. I think that moments like the current one are a lesson, to make some profit when it goes up
This is the importance of making a target or setting up some goal on your investments on which panic selling is never been a good idea because selling on loss is a dumb decision but it's not bad on holding for years but if we do see some pump then it's not bad to sell but it's up to someone since not all do share the same mindset.