How much room do you need to turn around?
Getting through the door is half of it. Once you're in, you have to turn. The 60-inch circle, the 30-by-48 clear space, where they matter most, how to check a room with a piece of string, and why it's a drawing decision.
Which floor should the bedroom be on?
A flight of stairs is part of the bedroom. Why one bedroom and a full bathroom on the entry level is the first decision in a renovation, why it's free on a drawing and a second renovation later, and what to ask if the bedroom has to stay upstairs.