You give up the time on one end or the other so the room can be cleaned.

I prefer more time in the room on the other end -- it's more important to me to be able to check in when I arrive in a city than to stay in the room late. I wish more check-out (and therefore check-in) times were earlier, 10am and 1pm rather than noon and 3pm. Get in, get settled, go have lunch, have the afternoon free, and no dealing with registration queues when you get back.

I do recall a 9am check-out somewhere, maybe India. Also, some hotels in Dubai just give you multiples of 24 hours from whenever you check in (or used to). That's nice.

Seth