We installed 4 of the First alert P1210 in late 2018. Of the 4 units installed (1 each bedroom and 1 hallway) All of the bedroom units have gone off at random times and for long periods without any reason. (no smoke, no steam, no spiders, no dust etc...) I've had to resort to trying to hit the little test button with a long stick as I'm not able to climb up to press it with my fingers. I have no faith whatsoever with these units. The previous smoke alarms we had for many years were First Alert that had replaceable batteries. They all functioned perfectly for many years. We were diligent about changing the batteries at least once a year and they did their job when we would accidentally burn something in the oven etc... They NEVER went off without reason and still worked just fine. So now the P1210 with the 10 year battery has a failure rate of 75%!! Taking them down to stop the constant ringing essentially makes them useless. We purchased them at Costco and I'm sure they will stand behind them. I'm not worried about that, I just want working units!!