I usually put the required smokes on the master bedroom lighting circuit. Too many home owners will turn off a dedicated circuit and throw the battery away rather than find out what is causing the smoke to chirp at them. The chirping is a trouble signal usally caused by a dead battery or a bad connection with the power.
If they cannot turn off the breaker because then the lights are out, the are more likely to fix the problem or have some one fix it for them.
A smoke is an item that we hope is never needed, but a life saver if it is working when needed.
