5 cats, two boxes. But they are indoor/outdoor cats so the frequency of cleaning depends on the weather. It's funny when they have to go when it's rainy or snowy. They will go from the front door to the back door as if the weather will change My D-in-law takes care of the upstairs box (where her three prefer to "go") and I take care of the downstairs box every time I go into the bathroom where I have it. Multi-cat hard clump litter. No problems.