Interesting indeed. We used to switch to 2000 when taxying off the runway except on those (still rare) airports where they require to use last assigned code until parked. Changed to allways keep last assigned code until parked and during preflight preparation for the next sector select 0000 until a new squawk is assigned with the next clearance.
We do not switch to off or standby though, the transponder remains in AUTO at all times.