This is always a hard topic, and it gets harder when you are in a relationship sharing pets. Both owners need to balance extending the pets life against the long term financial impact. You don't want to bankrupt yourself to extend their life by just a year, but you also don't want your partner to think you would heartlessly throw away the life of an animal you both care about. It's hard to balance that decision and you both need to be on the same page when the time comes.