Doug,At the very least I would check the circuit that connects the smoke detectors together and the circuit that it is powered from.It sounds to me that the detectors aren't too happy with the supply voltage they are getting and are doing a slow burn.To turn off the circuit, is just stupidity, you might as well not have them at all.Maybe it could be a manufacturing fault with the devices, it might pay to contact the manufacturer to find out if any others of this particular model have suffered the same fate.I would tend to hope that you would get more than 2 years out of a smoke detector.

- Brad Perkins (Candor, NY), 03/25/2017

Check if dust could be entering them from the ceiling void, driven by air currents.This can cause failure with false alarms.

- Jean P (Napili Honokowai, HI), 03/25/2017

I would check to see which device is causing the alarm. We had a problem that turned out to be the location of one smoke (in the stairwell). Don't know why that location caused the smokes to go bad but we moved it 5' over and it solved the problem. I would also check the orange wire that dasiy chains the smokes together for loose connections. Good luck Rod

- Dave Acosta (Rochelle Park, NJ), 03/25/2017