Depends on the dealership, but almost everyone I've worked for has employees driving used cars home when they feel like it. If its a nice car it hasn't been sitting the entire 6 months. Employees tend to drive the nicer cars more than the econoboxes but they're supposed to rotate them to ensure cars don't sit around for too long. The only thing that can get hurt from sitting around for a few months is the battery but any good dealer should be checking and charging the batteries periodically.