I'd recommend testing the batteries first....Smoke alarms don't take much "juice" and usually have 9volt batteries in them that have an average life of 3-5 years....Changing them yearly regardless of condition would be a waste....Not to mention that most modern smoke detectors will start to "chirp" when the battery gets low so they basically self-test constantly....
@EddyFree : That chirp, yes .... DH was over half deaf and hadn't been able to hear that chirp for several years, so it never bothered him. Only me. On my last trip inside our home, I noticed one had started to chirp. I was happy to walk out saying ... "Not my problem" ...