We have always done any day/start finish, from our own experience we know a Sat/Sat adds £40 per person with weekend supplements. Given that our villa will take 8 comfortably, that's £320 (in most cases that is enough to pay for most, if not all, the car hire for 2 weeks.

Also, if your budget/time doesn't allow for 2 weeks, or you have plans for part weeks, like most owners, we are happy to take 10 day bookings etc.