Replace Cat Litter Box. This information is not a substitute for a vet’s opinion. The more your cat uses the litter box, the less often you should change it.
The concern here is toxoplasmosis, a parasitic infection that can be transmitted through cat poop (such as in kitty litter or outdoor soil where cats have defecated). If you just have one kitty in your home using a standard plastic litter box, replacing it once a year is a good idea. However, some cats need to use a new box more often than others.