Our 16 yr old cat is just not using the litter box any more. It is not that he can't get in it. As well as his old one, I set up a shallow rubbermaid container as a litter box. I put him outside for a few minutes, sometimes he urinates, sometimes he waits and does it on the tile floor against a cupboard or dishwasher, or sometimes in the middle of the wood floor. He is not even sneaky about it, just goes ahead in front of me sometimes. Had him to the vet several times and told nothing wrong, just getting older, behavioral. I few weeks back I thought it was near the end for him as he was kind of staggering and not eating, then he bounced back a day later. His cry is weak now. Just don't know at what point do I know his quality of life is not what it should be. I haven't had to make this decision before.He is not in any apparent pain.