25 minimum and I'd do as many as they wanted. Some hotels are always busy so I could get 50 done. Some were more like suites with kitchens and had a lot of professionals all the time so those hotels stay 65-70% occupancy so much harder to get more than that.
We do all of ours ( 120 ) in two days. Occupied or not. Get the hotel to print a letter to gove to each guest as they check in so they are aware that you will be doing their rooms. Its good to use a porty on anything past the 3rd floor depending on your tm.