I had to put my childhood dog, Christy down when I was 20. She'd had seizures, lack of bladder control, hip problems for years. She didn't seem to be in pain and seemed like she had the will to live for a a few years. Then one day, she looked me in the eyes. It was like we understood eachother. She was tired and didn't want to get up anymore. We both knew that it was time. It was very difficult, but I think that deep down, you'll know when it is time.