Depending on environment, indoor kitties have a longer lifespan.
+9
I had three all make it close to 18 being near a trolley line, and heavy traffic (along with evil kids whose parents are equally evil).
Had a friend who recently lost his baby and the doctor speculated that it was rat poison. Whether it was ingested directly or indirectly, it's a big risk. My rule is to give them windows to look out and an open window, even if just cracked so that they can smell and hear things. I have one window that is on a ground level which cracks open maybe a quarter of an inch. I also give them things to chase by throwing their treats all around the house. It gives them their tracking and chasing practice/play.
I don't think I'm making sense, am I?