Liz that same thing happened to us. We had a Senior Schnauzer, Kona. At the time she was 15 (last year) We knew she was getting worse, arthritis, glucoma etc. We knew but could not bring ourselves to face it. We took her to the Vet and he gave her rimadyl (spelling?) and for eight months to a year she did well, even went down the stairs and slowly ran with the other two dogs. After that she started to fail, layed down all the time, lost control of her bodily functions, still we could not face it. We would say, maybe next week. That went on for a couple of more months, then one day we both cried and knew it was time. She was in pain and we were being selfish trying to keep her with us.
We didn't want to lose her. The day came and we took her down to our Vet and Don held her when she went to sleep. That has been the most difficult day in my life ever.I guess what I'm trying to tell you is that you and Buddy will know when the time comes.
You will think of Buddy no matter how much it hurts you. I hope this has helped you a little. Hugs and kisses to sweet Buddy.
Jackie