How often should you replace smoke detectors?
Every 10 years.
How to do it
Check the date printed on the back of each alarm. Replace any that are 10 years old, and CO alarms at the age their label gives, usually 7 to 10 years.
Why it matters
Smoke sensors lose sensitivity with age, even when the test button still works.
Recommended interval: every 10 years, per U.S. Fire Administration.
General guidance for a typical home; the manufacturer's instructions come first.