The normal life expectancy for a cat is anywhere between 13 and 15 years of age. Indoor cats generally enjoy a longer life span than cats who go outside. This is because while outdoors cats are more exposed to diseases and other dangers such as cars.
   A cat is considered a "senior cat" anywhere from 7 to 11 years and by the age of 12 years cats will begin to experience the effects of old age. Aging will be different for each cat. Some will look and act old at 10 years while others are active through their 15th year. What is happening as a cat ages is that each cell in your cat's body is programmed to last a certain time so the degenerative process is different for each cat. Vets recommend some type of preventative health care program for your cat as s/he approaches 7 to 11 years of age.