When you buy a new litter box, your cat will not start using it immediately. You have to get your cat acclimated to that. Place the new litter box in an area that has the highest pet traffic. Now, all you need to do is scoop a bit of your cat's used litter from the litter box that it previously used and put it in the new one. This will help your cat to identify the new litter box for its use. Within a few days your pet will begin to use the new litter box regularly.