My wife's a vet (now retired) and we've had LOTS of dogs over the years. They bring so much joy, but they live such a short time. It seems unfair that your best friends only live 20 years at most, and we love big dogs so it's more like 10 or 12. That's how all of our past dogs have ended up. Since we both have a medical background, we can take care of them longer than most owners would. We even adopted an elderly shelter dog with a tumor: The shelter folks thought we were saints for providing hospice care they couldn't. She lasted almost two years though, and it was a very good two years.
It's a shame we can't offer the same painless passing to humans. My mom is 92, non-ambulatory, and now her kidneys are failing. The assisted living place had Medicare buy her a crane so they can get her to the bathroom and in her motorized chair for the dining room. I hope by the time I get there, we have sensible end of life assistance.
"The pain now is part of the happiness then. That’s the deal."