Yup. A second wheelset will certainly cost more vs. the bother of taking 15 or 20 minutes or so to change out the tires twice a week. If you are trying to minimize the nuisance factor you can't just throw on any old set of new wheels either. You have to find a wheelset that is the same width as your other wheelset. Otherwise you'll have to readjust your brakes every time that you change wheels. That might take as much time as changing out the tires.