I got in on an earlier flight, and arrived at 6 it was a pain in the ass.. I literally had to walk around for like 4 hours until things opened, and I was so tired and weary all day.
If checkout is 11, you need to be able to clean dozens of rooms before check-in. You can't have 20 cleaners come in for an hour, so you have 5 cleaners come in for 4 hour shifts instead.