As I recently learned smoke alarms don't last forever - and they need to be recycled as hazardous waste if possible.
I was reminded again of the need to buy new ones periodically last week when I was trying to take a nap (with the poodle of course) to rest up from long days of business travel. We heard that high pitched beep of a smoke or CO2 alarm battery needing to be replace. I got up and removed the batteries from the CO2 detector since I didn't need a ladder to do that. 5 minutes later - beep. So I got the ladder, took down the smoke alarm and took out the battery. Problem solved.
Later that day I put in new batteries and put the alarms back. All fixed. Until last night when it happened again. I found the manual for the smoke alarm and oops - we bought it in 1996 and it has a 10 year life. Guess we got our monies worth on that one!
You might want to consider how old your alarms are and replace the alarm as well as the battery if needed! Be safe.