I wait as LONG as I can, and even do them one at a time as I need them if at all possible.  

BUT, I don't start appointments, or get info from clients until late January. 

I transfer all client by Feb 1st so I can use settings to track work flow.

YMMV

A warning to be careful if you do transfer some now/some later.  Make sure you don't re-transfer ones you've already done work on in the 2023 program.