Probably the only answer to this question from the op would be:
It is all dependent on an individual.
Why do you think there are so many exchanges and defi services offering you high interest rates so to hodl your bitcoins on their platforms.
Cause they know something is good with bitcoin and they would want to use them for leverage trading where ever they transfer those holdings too.
So for me, it would be never.
HODL til you die!
This is my philosophy when someone poses this question to me at the very least.
Indeed. It is still depends on an individual if when they're going to sell or hold. Everyone will obviously have their own analysis and they will obviously know when to do HODL or not. Hold is a common strategy when investing, as long as there is hope for profit, hold is better than selling. It will also depend on the coin you are holding. I suggest that holding is much better until you reach your goal but, there's a time also that selling is necessary, so, it will depend.