How Long Do Smoke Detectors Last? (2026 Guide)
Smoke detectors last 10 years from their manufacture date — not the day you installed them — under NFPA 72, and CO alarms enforce their own end-of-life clock under UL 2034. This guide shows how to read the date code on the back of the alarm, decode low-battery vs end-of-life chirps by brand, and walks a full replacement example.