I just recently experienced this same dilemma w/my Puddy. She'd overcome one hurdle, then something else would appear. I went back and forth w/the issue and finally had called my local vet and put her on alert that if I didn't see improvement w/in a couple of days, I'd help Puddy to the Bridge. As it turned out, though, I didn't really need to make the decision. She developed pneumonia and while my vet was getting everything ready to have her PTS, she died in my arms. Some people had been telling me that they felt it was Puddy's time but I didn't let that deter me. I've had to do it previously w/other cats and dogs but there was never any question that it was time. W/Puddy, we weren't so lucky. My point is that even though I agonized over how and when I would know it was time, I did know, finally. And you will, too. My heart goes out to you because I know how difficult it is for you. Sasha is your heart doggie; Puddy was/is my heart kitty. (((HUGS)))