We arrive on Saturday, and depart on a Friday. The main reason we do that is so that we don't have to be concerned about checking out of our timeshare early, as it's ours until Saturday. The other reason, of course, is to avoid the Saturday chaos at the airport. We find both to be worth the lost day. That said, we are on the island for three weeks; if I were only there for one week, I wouldn't do it.