I have two cats, 1 is 15, the other is 12. The 15 year old just started going right outside the liter box. I did not change liter or the box. She just recently had an operation and is on thyroid medicine. So my question is why did she stop using the liter box??
There are many different reasons why this is possible. Your cat may have a urinary tract infection, senility, stress, etc.. I recommend a visit to the vet for a check-up. vetcare