Two jumbo boxes for three cats using Fresh Step Premium. We scoop twice a day and I keep a tiny broom/dustpan to pick up the kicked out litter. No problem with anything uncovered because we have superfinicky Emily who does catbox patrol and makes sure EVERYONE'S business is covered. As for a total empty and scrub.. well, can't even remember when I last did that - many months I am sure, but there is no odor and we keep them in the same room off the hall. Once a week or so, I remove the boxes to vacuum and mop the floor really well under and behind, etc.