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
New ones had the same pigtail as the old one (both were Kiddie brand), but I did have one I had to rewire. As far as I can tell, they do not have a dedicated circuit, so I had to shut down the entire house.
Depending on the building code / age of house it may or may not be on an individual circuit.
I think newer homes don’t so there’s one less point of failure that can prevent them for going off in a fire. I could be wrong though.
Mine were Kidde as well. They were installed by my dad maybe 17 years ago when he built the home. I eventually found the breaker after a fun game of yelling “Is the light on?” I laughed when I found out it was on the same breaker as the septic aerator (which I had apparently also attached to a garage circuit overhead for work lights and ceiling outlets for tools due to the wall circuit overloading). Fun fact for the people who may not be familiar with septic aerators - when they lose power they have a box on a separate circuit for the failure alarm (which isn’t very loud but annoying af).