Smoke detectors (not just their batteries) have a temporary shelf life. Find out how long yours will last, and how to know it ...

When you move into or buy a new home, no one hands you a guide to how the smoke detectors work. They "chirp," which really means shriek loudly, and you occasionally have to put new batteries in them.

Ionization smoke alarms use a battery and two metal plates, called electrodes, to create an electrical circuit. Ions are tiny, electrically charged particles that flow through the circuit and between ...