Certainly when we've flown into Australia & NZ and arrived around 5am, we've booked a room from the night before so there is no issues getting into our room and getting showered/fresh clothes on. One of my friends doesn't book though and as a consequence, she's got to put her luggage into storage/hang around the hotel waiting for the first room to become available and sometimes that isn't the nicest room either! It was a tip we got off a work colleague and its definitely a great idea although as a disclaimer, the hotels weren't Marriott ones.