This is the hardest decision one ever has to make. When my Bailey was 14, my Vet said it "was time" due to a tumor that had been growing on her face and the problems it had been causing. I wasn't so sure because she still ate well and had a bounce in her step, but I could tell she was in pain. We went back and forth with what to do, and I cried and cried, and cried. We finally decided to end her pain and were going to take her to the vet when my husband got home from work that day; however, that very morning (of the day) she went into a seizure which didn't stop. As soon as the Vet's office opened, I carried her in. It was almost as if she made the decision herself so I wouldn't have to question it. My "dog of a lifetime" remained that to the very end.