I heard someone say, "Thank God they don't live 30 years, we could never bear the pain of losing one after that long."
My husband and I have always had pets, even favorite chickens, mille fleurs - Lester & Lucille. A cougar got Lucille one night, and broke Lester's leg. We amputated it and he lived on for another year.
Our next to the last German shepherd was put to sleep on 9/11/1999 at the age of 14 years. He could barely walk.
Swearing never to go through that again, and knowing we were too old to have pets any longer, it happened that a young German shepherd arrived on our doorstep in November, 2002. We couldn't resist - he was so smart. But, it only took a few months to realize that it wasn't fair to the dog. He needed more exercise than we were capable of giving him. So, we gave him to a law enforcement officer, who wanted to train him as an FBI sniffer. He's in Montana now, probably happy as a lark.
Having been an "owner" of 'em all, it has been my opinion that cats live too long, and dogs don't live long enough.
Try having an tabby cat for 22 1/2 years - broken teeth, arthritis - can't get all the way into her litter box, plus meaner than sin, it still took 4 cancelled appointments with the vet before we finally did it.