The PetHub Family Plan protects as many pets as you can fit onto your PetHub.com account (and that's a lot). Simply purchase the upgrade and all of the pet profiles you add to your account will then show "Premium."
As long as your account remains in good standing, you are locked in at the $99 / year subscription rate, even if our prices go up!
Considering PetHub charges $49 per pet for a Premium subscription, the more pets you have in your household, the more you save. So go out and adopt another dog or cat! :-)