I had no idea of its life-extending effects. Those poor animals in my game are going to live forever!
I find that the gourmet pet food thingy is a bit too much of a hassle for me, not to mention I have the Bottomless Pet Bowl LTR and that gives pets who feed from it a rather nice moodlet as well. And when my pets are nearing the end of their lives, well, I just purchase the Young Again Potion for Pets, haha.
Playing on a normal lifespan, it is usually more than enough for pets to accrue the LTH required for the potion since their wishes are often pretty simple and easy to accomplish: in fact, I only need to promise the wish and a lot of times the pet in question would fulfill it autonomously.