tough one man. It's not easy for sure. My wife and I have had to put down 5 dogs since we've been together. One was 17 years old and I think we held on too long. Similarly, she had good days and bad days. On the bad days we'd muster up the resolve to go through with it and then the next morning she be like 5 years younger and we'd change our minds. She had heart degeneration. My wife had that dog since birth and helped her through two divorces of her parents and some really hard times. We held on way too long. Two other dogs we had together were Greyhounds. A lot of love in short lives. Cancer and joint problems made it a very decision because mentally, they both were alert and very loving to the end. Another one was another adoption and we only had her a short time. The last one was a Rottie I had all her life. The typical story of a dog who would jump through a firey building, across country, and hell and back for me and my family. That was the hardest decision I had to make in my life. She was always an arrogant and proud dog. I didn't want her going as just a shell of her former self. I cried for 2 days and didn't get another dog for over a year. Best hindsight I could give you is that it was the toughest decision I made but don't regret it. To this day my most vibrant image of my wife's dog is that of her last days when she was with us too long. For my dog, the timing was right. My fondest memories of her is taking her camping, fending off a robber at my dad's shop, and playing ball on the floor with my then 1 year old son...the night before her last. As you weigh your decision, just don't be "selfish", if you can understand what I mean. Thoughts and prayers as you struggle with this.