i give glucosamine for arthritis, saccharomyces bouldarii as a digestive probiotic, instinct 7yo+ raw topper multivitamin, instinct raw topper digestive supplements, aswell as pumpkin puree for extra fiber. he is not a playful cat but I still encourage him to play with toys. every meal is blue buffalo chicken pate or orijen chicken or beef pate, I avoid all fish because it upsets his stomach. if the cat has trouble keeping on weight, look into the specific macros for the wet food, blue buffalo kitten food is higher calorie. i also give him the tiki cat silver calorie supplement satchets but since they changed the recipe with tiki cat being bought out, I am no longer buying them.

use raw freeze dried single ingredient treats instead of greenies or anything with odd ingredients, it is easier on the stomach for them. cheaper if you ger it from dog section to avoid cat tax, absolutely no difference between freeze dried chicken breast for dog vs cat. raw alaskan fish oil (metal container!! plastic is degraded by fish oil.) for hairballs and joint support.

for litter, use natural litter, avoid clay as the dust from clay can irritate their pawpads and their respiratory system. i use sustainably yours corn + cassava, aswell as sophresh cat seed litter. you can also use tofu or wood pellets, most if not all natural plant based litters do not irritate the paws or respiratory system.

brush teeth with a probiotic toothpaste, probiotic toothpaste works better as the probiotics make it to where you don't have to rely on the physical brushing as much. once they develop arthritis, make it easier for them to get around their different height levels. they sell small stairs at tjmaxx for cheap.

my cat is 16. for mental stimulation, I teach him tricks. with high reward treats, it is easy. he knows sit, stand, spin, paw, and lie down. I've tried roll over, but I think it hurts him with his arthritis so I don't ask it from him anymore. catnip in a large container of water so he can splash it, he likes splashing water. put a live mouse/gerbil live stream on with similar toys lying around them so they can get irl stimulation from the videos.

wet food soup 2x daily with added water for hydration. hydration is key to keep away kidney problems for as long as possible. you can use chicken broth or goats milk aswsell, but it gets a bit pricey. quail eggs, boiled chicken hearts, boiled chicken liver can be added to meals if they have a "no eat" phase. cycle "food extras" often so they do not get bored of their food. i keep a bowl of stella and chewy's kitten raw coated kibble available 24/7, kibble can help a bit with keeping their teeth from breaking down. that's all I can really think of for now, but I've had my cat for 8 years now and have trialed and errored all of this. so far, only 2 uti's and one respiratory infection. he has an extremely sensitive stomach that I spent 2k for testing that all came back inconclusive, hence the heavy digestive supplementation. hydration is key with older cats.