Last year we had the 7 day hopper and we were ther 7 nights leaving no ticket for the last day if we needed one. Our plane wasn't leaving till 6 at later in the day. So we wanted to go to EPCOT and needed the 8th day so we went to the fornt desk and added a day and it was only like $3-4 but we were checked out and this took a while for them to figure out. So you can upgrade your ticket while still checked in if you would need a ticket for the last day. You may not need the extra day if you do a day at Typhoon Lagoon or Blizard Beach but if you do you can always add it later in the week while you are there.