I understand that keeping their teeth clean adds years to their lives - one of the cats I had when growing up eventually died after a tooth got infected, at the age of 16 and she might have made it to 20 or beyond if the practice of cleaning teeth was in place at the time. But I can't bring myself to be *too* overly concerned as they normally live for 2-3 years in the wild, and having 16 is way more than they evolved to do.