The vet is great -- he makes it a point to see her personally and calls her his "miracle kitty." He is sure Musica is his oldest client of any type of animal (I assume he doesn't have sea turtles on his clientele list).
FWIIW, Musica has alwas been 100% indoors -- I think that makes a big difference. Of course, she has always been ornrey and egocentric. I think giving in and letting the cat knows she IS the center of the universe helps a lot, too ;)
The three torties I have now are 100% indoors. All were more or less rescues, but only one came to me as a kitten (she's now 5 years old). The oldest is nine years old. The youngest is a little over 1 year, and was trapped as a feral.
I recently made the decision to go with a fairly expensive brand of cat food, Innova Evo, in the hope of keeping them healthy longer and keeping expensive vet visits to a minimum. It's a dry food, but it's grain-free and low-carbohydrate (which sounded like a good idea to me because cats are carnivores). I also give them other goodies, such as fresh meat, good canned food, fresh butter, and yogurt, once in a while.
They absolutely love sprawling on our porch, which has sliding glass doors and screens. I know they would love outside adventures, but (1) the landlady doesn't like cats running around and messing up her careful yard work, and (2) I know that letting them outdoors shortens their life expectancy.
My first tortie, back in the early 1990s, only lived about 2-1/2 years because she refused to stay indoors, even after being spayed. I took her with me to TN for a year, and she did fine, running around outside, under the house, etc.
Then, a few months after I came back to CA, she literally just ran under the wheels of a car one night (I was away at a friend's place for Thanksgiving dinner). My roommates told me about it the next day. The ironic thing is, the street where I lived in TN was a lot busier, in terms of vehicle traffic, than the street I lived on later in CA. I was heartbroken... and I also fell in love with torties while I had her.