When you look at the current research on spaying and neutering, the AGE at which it's done turns out to be vitally important to your dog's future health. For example, your female dog should NOT be spayed at 6 months old.
Life Expectancy of Dogs and Cats. We hope our pets will be a part of our lives for many, many years but the fact is that the average life expectancy is 10-12 years for dogs and 10-14 years for cats. Older pets have very specific needs and are particularly susceptible in later years to cancer, arthritis, and dental disease.
In general, a kitten is considered an adult cat when it reaches 1 year of age, but your cat may not actually be fully grown at this point. Kittens typically reach a length and weight close to their full-grown size by 9 to 12 months of age. After the 1-year mark, most cats continue to grow at a much slower rate until at least 18 months of age. Large breeds, such as Maine coon cats, typically take even longer to grow to their full size. These cats may not be fully grown until they reach 2 to 4 years of age.