If you see a BTC trend then holding is better. But everyone has their own opinion.
If I choose three options divide between BTC, USD and altcoins. I use this for backup because it could be wrong predictions for what I have.
Several times I have sold some of my BTC out of necessity. Otherwise I will store and multiply BTC.
I am not selling firstly at lesser price, secondly since I am a long term investor so such falls does not shakes me actually. As well, if have some funds or can manage to save anything extra for that month then during dips I invest more in bitcoin as it will always have a good bounce back in future.