They say cats have nine lives, but eventually that ninth life comes along.

It’s not always easy to tell a cat is aging. Senior cats may show some gray hairs around the eyes and mouth, the lenses of the eyes may cloud over, and they may think twice, then walk away instead of jumping onto the kitchen counter.

The average life expectancy for cats is 10 to 15 years, although some live into their late teens or even 20s. Cats are considered mature at 7 to 10 years of age, senior from 11 to 14 and geriatric over 15.

“This can vary a lot between cats depending on their breed and health status,” says Dr. Matthew Kornya, a veterinarian who practices in Ontario. “In humans, some 70-year-old people are healthier than some 50-year-olds, and the same is true for cats.”

Fortunately, you can take steps to ease your cat into its golden years — and possibly even extend them.

“Cats are already living significantly longer than they were just 10 years ago,” says Dr. Drew Weigner, an Atlanta veterinarian who specializes in cats.

“Advances in treating many diseases seen in older cats, such as kidney disease, diabetes and thyroid disease, have led to not only increased life span, but also increased quality of life,” Weigner says.

Keeping weight off is key. (If you need to be convinced of that, check out the videos of Cinderblock, the 25-pound cat bewailing its exercise time on the water treadmill.)

Excess weight stresses joints, leading to painful osteoarthritis. So it’s better if your cat never packs on the pounds in the first place. Measuring food, hiding small amounts of food around the house so it can hunt for it and scheduling three to five minutes of playtime a couple times daily are ways to help cats stay trim and active.

Some aging cats have the opposite problem, losing lean body mass with age. Smaller, more frequent meals and a fountain to encourage water intake can help them to maintain good body condition.

Senior cat dietary needs vary by individual. Some become less able to digest fat, while others have a diminished ability to digest protein. Cats with chronic kidney disease can benefit from therapeutic foods to help manage their condition. Other diet-sensitive conditions include cognitive dysfunction, diabetes mellitus, hyperthyroidism and osteoarthritis.

Your veterinarian can help you choose the best food for your aging cat, but, in general, a highly digestible, nutrient-dense diet is a good choice.

You will want to evaluate your cat’s environment to see if any changes need to be made. It may be time to rethink putting the litter box down a steep set of stairs in the basement. Placing a food dish on top of the washing machine to keep it out of reach of the dog may have worked well in your cat’s younger years, but it may not be such a good idea now.

“Make sure cats can easily get to food and water or their litter box without it being a stressful climb or difficult place to get to,” says veterinary technician Harmony Peraza at Texas A&M College of Veterinary Medicine.

Be on the lookout for changes in behavior. Take your cat to the vet if it suddenly starts drinking lots of water, eating less, not using the litter box, producing only small amounts of urine, prowling or yowling late at night or grooming less thoroughly.

“Arthritis commonly affects older cats and may lead to reduced mobility, inability to groom themselves and difficulty using the litter box,” Kornya says. “Minimizing arthritis pain can dramatically improve quality of life.”

Dental health is also of crucial importance, because many older cats suffer from tartar, gingival disease and oral infections that cause chronic pain and may lead to systemic disease.

The goal is to keep your cat as healthy as long as possible. And a healthy older cat is free of pain and infection, well groomed and has a healthy body condition.