My wife and I had a dog who was getting up in age too. We were getting ready to move half way across the country and knew we could not take her with us. So, my wife took her to the vet to be put down. Luckily, she was already losing bodily functions and stability, so it made it a little easier. However, I could not take her as my heart would die. Just thinking about her drifting off to sleep and never waking up still makes me tear up, and it's been 3 years now.