Incredibly helpful to have buffer days if you can manage it. A very short rent-back agreement for a few days smooths out a lot.
We sucked up an extra month's rent to have overlap on our move just across a small metro area to the older house we'd bought, and it was worth every penny - we had time to repaint some walls and refinish the living room floor before our furniture was moved in (local moving services in Germany are quite different from the nightmares I'm hearing about here)
Yeah, create overlap in some fashion. Anything with zero margin is error prone.