A cat likes her litter box kept spotless, so you need to make sure you clean it regularly. You need to scoop out any feces and clumps of urine (if you use clumping litter) at least once or twice a day, but preferably after every time your cat uses the litter box. You'll also need to completely empty the box and refill it twice weekly for non-clumping litter and at least once every two to four weeks for clumping litter.