^ Agree with above. Have had luck with getting a room in the morning (in Europe). Even if the room is slightly different than booked, I take it. Not picky, just need a bed to catch some sleep.

Also, if sleep/shower is important, book an extra night in advance for a guaranteed room and notify hotel in advance you will be coming in the morning, so you are not marked for no show.

There are also plenty of day use rooms as an option by the hour.