If your cat has been "knocked" for more than 10 years, then she, most likely, has already entered the age of maturity, and special care is needed. Grandmother cats have a complex character and, often, a whole bunch of diseases.
Older cats usually take short breaks while playing. This is normal. It's too early to worry about the health of loyal friends. But if the cat completely refuses to play, falls into apathy, this is a reason to think about her health.
If during rest the cat does not just sit, but stretches out on its side, perhaps these are the first signs of rheumatism. Make sure that there are no drafts in the room and that the cat does not lie down under the doors and under the windowsills, since this is where they most often blow out.
Older cats get cold quickly and often catch colds. You can avoid this by increasing their fat levels. Give them more food that is high in fat and fiber (ideally fatty cottage cheese or adding droplets of fat to a vegetable treat).
Changes in the spine are very painful for the cat. You can accidentally hit the affected area of the vertebrae when you pet the cat - it will react very violently. Such a cat should be handled with care and must be shown to the veterinarian.
Dental disease is just as bad for cats as it is for humans. Think about how you feel when your teeth hurt. Likewise, cats - if their teeth become inflamed, they become aggressive, irritable, prefer to hide, they salivate strongly, they refuse food. You need to immediately show the cat to the veterinarian. Usually the problem lies in the "flea teeth" (they become inflamed), this is treated.
Eating food for an elderly cat is an important time of the day. Therefore, you need to be smart about making the menu. Cut the meat into thin and elongated slices to make it easier to chew. Potatoes and solid food must be crushed to make a puree. The total amount of food dispensed should be divided into 3-4 portions. It is better to feed less, but more often.
Keep food and water in bowls fresh at all times. Do not experiment with the weak stomachs of "old ladies".
If your kitties have weaknesses and whims, it is better to indulge them. Cats are naturally stubborn creatures, and even more so in old age. Considering how much warmth and kindness this faithful creature gives you, try to make her life easy and pleasant.