This is a very difficult question to answer. I've had to only put one of my furkids to sleep before and I wanted to do it before he was too far gone. I always tell people that their furkid will let them know when it's time and I believe this. Hopefully your vet will help you decide what's best for Guy.

If he does have arthitis then maybe you could try giving him some cosequin. I've been giving this to both Sunny and Storm but for their bladder instead of arthritis because it's also supposed to form a protective lining around the bladder to help protect them from UTI's. Storm will be 10 in January and he's still very frisky and active so I know that this will help keep him active too. I order mine online.