My First Alert smoke detector model P1210 sounded off at 4 a.m. for no reason about a month ago. I have two more of the same model and gave one away to a friend since I already had more than I required. So far, only one detector has acted up. But today, to be on the safe side, I’m backing up the remaining detectors with a different brand. I intend to give the loud one a second chance, just for kicks, but I can’t trust it. The Unit was manufactured on 7/9/17, and installed late 2017. All the units are properly located according to the instruction manual and not in an area of exposure to triggers.