In our higher-end work, we install, sand and seal the hardwood, then cover it, do the trim and painting, then un-cover the floor, and do the finish coats. Not every schedule can work to this, and the floor finisher's gonna want a little more money for splitting the job in two, with maybe a month in between. It's our preferred method for kitchen floors, because they get sanded straight through, uninterrupted by the cabinets/island. And the cabinets don't get bumped by the sander.
Casey