I have 5 cats and 5 litters for them around in different parts of the house. They all use each one of them, but by having them separated around, the kitties have complete privacy to go potty. I've had to do this because my little "devil" Oliver will wait and ambush attack the other's as they exit the litter door. This way Oliver doesnt always know when one is pottying.

I have found through trial and error, a solution that works every time for me when I have a kitty and even grown cats that have decided the floor, or the laundry would be better to potty in. The minute I notice this, I put a litter and the cat in the bathroom for a couple of days, or until they have used the litter faithfully everytime the go potty. Confining them to a very small space with the litter will correct the problem everytime!

Trust me, this is not mean or cruel or abusive. You still love kitty and he/she will know it by your frequent visits to reassure them they havent been forgotten. It's the best way to train or retrain your kitty when they are being really stubborn!