Yesterday while cooking I set off the smoke detector, no I did not burn anything. They go off when I cook over a high heat. And yesterday once they started going off they would not stop. I ended up having to disconnect them all (they are hard wired with an interconnect) and I replaced them this morning. Aaaaaaaand let me tell you, I had a sleepless night last night knowing there were no detectors installed.
https://www.southernliving.com/how-often-should-you-replace-smoke-detectors-8774122
The closest detector to the kitchen was in a bed room.
There had been a different detector in the living room but had gotten knocked down a while ago and broke (and never replaced), it was not on the interlink system, and when the other detectors would go off while cooking the one in the living room would not.
As you can see from my image, the detectors I replaced were from 2005, and needed replacing for quite some time.