Depends on what you are trying to accomplish.
If you are trying to protect the painted edges:
Getting aggressive with compounding...taping the edges off, does provide some additional safety.
For polishing, IMO, it is overkill as the likelihood of damaging the painted edge with less aggressive pads and polishes is greatly reduced.
If you just want to keep compounding dust out of the hinges and door jambs...tape to your hearts content. Opening the door and doing it from the backside will allow you to polish all the way to the edge of the panel.
Personally, I try not to buff over these gaps at all. I prefer to tape off the edge of the panel adjoining the one I am polishing to protect that edge. If you overlap the tape into the gap, it will prevent a lot of dust from getting in the gap.
Helpful Hint....when taping off window trim, make sure you cover where the window meets the trim. The velvet seal will sometimes hold on to compound and smear the window and possibly scratch it, when lowered and raised.
My $.02