Hi,
My house has hard-wired 120v smoke detectors. One went off today for a few
seconds. So I climbed up to take a look, and I noticed on the plastic
housing it says replace by year 2005. I tried the test button and it
worked, I actually tried the test button on all the detectors and they all
worked. Should I replace all the detectors? They seem to be working, based
on the test button. I know there are recommendations on replacing battery
operated ones but not hard-wired ones.

Thanks,
Jeff