When it was time to euthanize my old dog, Lacie, I knew. I had been wondering for about a year, "Is it time? No. Maybe. Next month". But on the day that it was time, it was time, and the decision was peaceful.

She was deaf and almost blind for a couple of years, but it really didn't seem to bother her. She was thin, and not terribly interested in food. But, then she started to get confused. She would wander around the house, and not be able to find the dog door or the food bowl until I showed her. One night I heard her howling, and got up to find her stuck in the corner of the room. She had been walking along a wall, and when she came to another wall, she didn't remember that she either needed to turn the corner or back up. So she just stood there with her nose in the corner, in a panic, and howled. She did the same thing several times the next day. She also was losing control of her bodily functions. I knew it was time ... to be deaf, blind, and so confused by life that you don't remember what a corner is ... that was no life.

OTOH, I have had many customers who held onto a dog way too long, IMO. One little poodle sticks out in my mind. The dog was ancient, like almost twenty years old I think. She was blind, deaf, frail, thin, ill, etc. She had no control over bodily functions, so her owners kept her in diapers in a crate. I felt so sorry for that dog. It was beyond time for her.

I think as long as you keep sight of what is best for the dog, and not what is easiest for you, you will know when the time comes.