@Angela1308:
The more limitations you place upon guests the fewer bookings you will have. Why are you choosing three nights instead of two nights or even one night? If your cleaning costs or some other cost prevents you from earning a profit with one or two night stays then I can understand placing a limit, however you are missing a percentage of travelers who will not stay as long. I usually place a two night limit for reservations made 60 days or more in the future as well as longer limits over holidays to prevent one-nighters from booking in the middle of a holiday period. Bookings made less than 60 days are able to book for one night.