I love that assessment.They do. What is difficult though for people is the ability to read those signs. I have seen many animals in their last moments, more times than not, long past due. They look so miserable and are often in poor condition. Quality of life involves more good days than bad, older animals will have bad days but they should not be consistent. Ability to move about their space, even if it is not as energetically as before. Eating and drinking without GI Upset. Interest in their people and things they love. Ability to go out to potty( Obviously cats/dogs/mammals). If one or more of these areas is compromised for an extended length of time, quality of life is drastically impaired. No one looks more defeated than a dog who can no longer go out to potty, making a mess in the house when they know they need to go out, just as they have been taught and expected to their whole life because that doggo is the bestest girl or boy. The saddest eyes belong to kidney failure cats, they are so sunken, their bodies very frail. I love animals, I understand their owners love them too, but the most loving thing anyone can do is let them go before they begin to suffer.
Last December, our little 11 year old Biewer Terrier passed away. She couldn’t do the stairs on her own, and if she got too excited she would have some trouble catching her breath. She was slowing down and a bit more sensitive than she was in her younger years. It was never anything that we felt like decreased her quality of life. Like you said, she was having so many more good days than bad days. She would come kayaking with us on the lake, she was beg for little treats at the dinner table, and she would snuggle up in bed with one of us at night. One day she was a bit slower than usual, her breathing was a bit different, a bit more forced and labored. We noticed. We all knew she was getting ready to go. She wasn’t in any pain, she was acting normal, just like every step took a bit more effort. We decided to keep her comfortable until Monday, so we could take her to our vet. The next morning, she slipped out the door with one of the other dogs. A couple hours later we found her laying on the outside patio in a warm patch of sun. We had family tell us we neglected her and let her go too long, that she shouldn’t have had to die on her own or whatever. People who don’t know your dog don’t get to say (unless they are a professional or you are actually neglecting your dog) but we weren’t neglecting her and these people had never had a dog before.