The average lifespan of a domestic cat is 12-15 years, although some cats can live up to 20 years or more. The factors that influence a cat's lifespan include diet, genetics, lifestyle, and access to veterinary care. Cats that are kept indoors and receive regular veterinary care tend to live longer than cats that are allowed to roam outdoors. Additionally, cats with certain genetic conditions may have shorter lifespans than cats without these conditions.