We purchased a 17-year-old home in Florida (USA) a few months ago, that has seven smoke detectors (one in each of its four bedrooms, two in hallways, and one in the main living space).
A few days ago, the smoke detector in the main living space began going off in its alarm state in the middle of the night. After verifying it was a false alarm, I silenced it and we all went back to bed. The next day I checked all 7 units and found four of them were original to the home, including the one issuing a false alarm. The interconnect wires were all disconnected as well. We decided we would go ahead and replace all 7 and interconnect them.
So far, I have done two replacements: the guest bedroom and the main living space. This morning, the one in the guest room began alarming which triggered the living room alarm as well.
Is the likeliest explanation that we're just unlucky--that we had an aging alarm that went into alarm state because of its age, and a few days later had an insect or something crawl into a different alarm? How can we troubleshoot this? My wife and son have sleep issues, and anxiety that at any time the smoke detectors may begin going off is not helping. Not to mention the damage to sensitivity that repeated nuisance alarms may cause if there is ever a real fire.