The aging process for our pets varies based on many factors. It is commonly thought that 1 year of a dog’s life is equal to 7 years of our lives. This is incorrect. The first 1-2 years of a dog’s life are when the dog reaches maturity. The aging process then differs on the size of the dog. Smaller dogs tend to live a few years longer than larger dogs on average. Health, exercise and diet also affect the aging process in your dog. Most breeds of cats are considered “old” at about 8-10 years old.