If you build the coop so the floor is at 3-4 feet,
4 feet would be too high to clean easily unless I had steps up to the access door. I'm only 5'3" so I wouldn't want my coop up at armpit level.

I put my roosts in Neuchickenstein at 4 feet anticipating a build-up of bedding. For the roosts of a walk-in 3-4 feet is a convenient height for doing night exams.