I hope this is an appropriate place for this question. It isn't country-specific and doesn't really fit any of the thematic fora (transportation, money-saving, etc).
I've always just proceeded to my hotel and either dropped off my bags or been pleasantly surprised to find that there's a room ready for me. But usually that happens when arriving 2-3 hours before official check-in time.
But what if you're arriving say 8-10 hours before check-in? Does anyone book their room for the day before arrival and let the hotel know you'll be arriving at, say, 7 a.m.? (Obviously you want to take care not to be interpreted as a no-show.)