When is it (if ever) the right time to put a dog to sleep?

Max has been with me since 1997. I adopted him when he was 4 years old. Someone had abandoned him – left him tied to a doorknob of a vet hospital. As with many pets, Max has brought me more joy, laughs, and companionship that I possibly could have expected from him going in. He’s been a great pooch. I really can’t imagine the last ten years without him.

His health has deteriorated quite significantly over the past two years. He has seizures that prevent him from using his entire “rear half”. He struggles to get up but his legs just don’t work. Eventually, after a few minutes, he recovers.

He is well over half blind and well over half deaf. He bumps in to things head-on each and every day. If you don’t yell his name, he doesn’t hear you.

He can’t stand up very well anymore. It looks like it’s often all he can do to keep his balance. He also can’t do stairs very well anymore. I have to walk behind him with my arm ready to catch him when he falls (which has happened on more than one occasion).

He is uninterested in playing ball, and he can’t walk quickly (much less run). At night he paces almost constantly. All night long. During the day he is completely alone.

I found myself wondering this evening, for the first time, “When does his quality of life (or lack thereof) outweigh my own selfishness of wanting him around?”

Any advice is welcome and appreciated.