if you don't know why to move, you're probably in the right spot.
You will know, when it's time to move.
e.g. if someone you like interacting with is blocked from mastodon.social, maybe not for a good reason, you could move.
another one: if you don't like policy changes of mastodon.social, you could move.
There's indefinite reasons, why someone would want to move. If you don't have a real reason to move, you don't have to 
