My bf's cat, who I currently look after, is about17 by now. He is an indoor cat and my bf said has never had health problems; he throws up occasionally when he eats too fast or has hairballs but other than that he is ok.
I have had cats all my life. My very first one, Missy, I don't know how old he was when he died. He used to go out a lot (all my cats back home did or do) and one day he disappeared.
He came back about a week later and he wasn't walking properly and had like something powdery falling out of his ears. He went to die in the canteen before we could do anything for him, poor him

. We thought he must have been beaten up by someone.
The following cat Flipper was very naughty, he was hit by a car, I think he was about 2. Same thing happened to Felix (he looked like that Felix yes). We found him one morning in front of our gate. He seemed ok, even though he had been hit by a car. He was even walking. I came back from school and mum said she found him dead in the canteen and then buried him. I know he should have been taken to the vet but mum couldn't take him by herself and dad wasn't home, the cat died before we could take him. He was about 2 as well (maybe 1).
The next cat was Mozart. He disappeared and we don't know what happened to him. He used to be out all day and just get indoors to eat. My sister was devasted when that happened, she looked for him everywhere, contacted an association and they thought hey had found him (dead) but when she saw the picture of the poor dead cat, she saw it wasn't him even though he looked almost the same. I hope he was simply stolen and he is still alive somewhere (not likely though as he didn't let people get close). He wasn't even 3. My mum still cries if she looks at his pictures.
She got a new cat, female this time, Margot. She is half Norwegian, half Persian and she goes out but doesn't go far, she is always close to the house or in the garden. She spends time lots of time indoors. Hope she gets to live many many years.