The Smartwares RM218 smoke detector was in our endurance test from September 6, 2015, to January 14, 2019.
After 3 years and 120 days The long-term test had to be aborted due to repeated false alarms within a very short period of time. Based on numerous customer reviews, some devices also appear to be experiencing battery life issues.

Oh fucking great. And I'm guessing the only way to turn the thing off is permanently, which I guess I'll have to do before going on a trip if I don't want my neighbors to hate my guts.