Ever been driven crazy in the middle of the night by a chirping smoke detector? One of your detectors has a dying battery, but determining which detector is chirping is surprisingly tough.
Instead of trying to figure out which smoke detector has the dying battery, just replace the batteries in all the smoke detectors at the same time to eliminate the guesswork. Also be sure to replace any smoke detectors that are older than 10 years because they’re no longer reliable.
If there’s no manufacture date on any of your smoke detectors, just replace them to be safe. Some newer ones have 10-year batteries in them that you never have to replace; you just replace the smoke detector.