That is the hard part the "future". I've heard a certain amount of time too, like you said 24hrs. What strategy are you using and is it working for you?
Yes, indeed, the waiting & timing part is key. It not enough just to wait it's mostly about constantly following news about your coins and selecting the correct time to sell.
I am a go big or go home type of person so, I'm going to wait for the long run when there are substantial price increases and all the cryptos are on a bull trend.