I just got put on notice that it's time, now that Thomas (the cat in my avatar) is 15, that it's time to start keeping an eye on his kidneys. His last bloodwork, done 3 weeks ago, indicated a slight rise in SDMA (a tiny bit above normal) The other two numbers are well within normal range. My vet says he's remarkably healthy for his age...other than needing a new skeleton. (His arthritis isn't improving with-age. The wonky heart and lungs seemed to have cleared up now that he, who had a few crystals in his urine, and Squeaky, who is a crystal factory and has other her bladder issues, are on Royal Canine, urinary S/O.
Neither will eat wet food. Thomas doesn't eat wet food of any kind. Squeaky will small amounts of some commercial wet foods.
Squeaky is now 12, so I've got one senior and one geriatric cat, both on chronic medications.
Thomas for pain and constipation, and Squeaky on fluoxetine (Prozac) of all things. Laugh or not, but it does wonders for her anxiety and makes her much happier cat in general.