I assume you are talking about cruise ships? If so, they replace all the linen and towels, clean the bathroom. Clean the other room and make sure all the junk is gone. Check to see if the next people in the cabin want 2single beds or a double and rearrange the beds. Make the beds. Restock the bar fridge. Vacuum everything. Check to see if the next people get anything special. Reset the temp to the normal setting.
Then they go on to the next of probably 30 or 40 cabins that they have to do in 3 or 4 hours.