It is a hard and difficult decision to make. I agree with red you will never be satisfied with, but it will be the right one. We've lost 4 cats over the last 8 years - 2 had to be put down and 2 died in their sleep. Right now my dog(lab mix) is 15 and she's a little shakey on her feet, stumbles and will fall sometimes, her appetite isn't good, I started mixing hot dogs in her dog food. I know the day is coming. We have 7 cats - 18, 16, 8, 8, 8, 3, and 3. Keep us posted.