The short answer
Every 10 years from the manufacture date. The U.S. Fire Administration (USFA) says, "Age matters when it comes to smoke alarms. They need to be replaced 10 years from the manufacture date." For every type of alarm, the USFA says to "Test the alarm monthly." Battery steps vary by type: 9-volt, hardwired, or 10-year (long-life) battery.
The 10-year rule
"Age matters when it comes to smoke alarms. They need to be replaced 10 years from the manufacture date." (USFA)
The clock starts at the manufacture date, according to the USFA.
What to do, by alarm type
The USFA lists separate steps for each kind of alarm:
| alarm type | test | battery | replace the whole alarm |
|---|---|---|---|
| 9-volt battery | "Test the alarm monthly." | "Replace the batteries at least once every year." | "Replace the entire smoke alarm every 10 years." |
| Hardwired | "Test the alarm monthly." | "Replace the backup battery at least once every year." | "Replace the entire smoke alarm every 10 years." |
| 10-year (long-life) battery | "Test the alarm monthly." | (no yearly battery step listed) | "Replace the entire smoke alarm according to the manufacturer's instructions." |
(All quotes: USFA.)
The monthly test applies to all three types.
Where to put them
"Put smoke alarms inside and outside each bedroom and sleeping area." (USFA)
"Put alarms on every level of the home." (USFA)
Hardwired alarms: who installs them
"Only qualified electricians should install hardwired smoke alarms." (USFA)
Keep a replace-by date for each alarm
This part is our tip, not USFA guidance: once you know each alarm's manufacture date, write its 10-year replace-by date somewhere you'll see it, like a shared calendar. For a long-life battery alarm, note the date from the manufacturer's instructions instead.
Quick checklist
- Test every alarm monthly (USFA, all types).
- Yearly battery: replace 9-volt batteries, or the backup battery in hardwired alarms, "at least once every year" (USFA).
- Replace the whole alarm 10 years from the manufacture date, or per the manufacturer's instructions for 10-year battery alarms (USFA).
- Check placement: inside and outside each bedroom and sleeping area, and on every level of the home (USFA).
- Write down each replace-by date (our tip).
Limitations
This page quotes the U.S. Fire Administration's smoke alarms page (last reviewed September 28, 2026). It doesn't cover every alarm model. For 10-year battery alarms, the USFA says to replace the entire smoke alarm according to the manufacturer's instructions. The replace-by date tip is ours, not USFA guidance.
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Frequently asked questions
How often should you replace a smoke alarm?
The USFA says smoke alarms "need to be replaced 10 years from the manufacture date."
How often should you test a smoke alarm?
The USFA says to "Test the alarm monthly." That applies to 9-volt, hardwired, and 10-year battery alarms.
How often do you change the battery in a hardwired smoke alarm?
The USFA says to "Replace the backup battery at least once every year."
Where should smoke alarms go?
The USFA says to "Put smoke alarms inside and outside each bedroom and sleeping area" and to "Put alarms on every level of the home."
Sources and further reading
- U.S. Fire Administration (FEMA): Smoke alarms (last reviewed September 28, 2026)
- U.S. Consumer Product Safety Commission: Winter weather safety tips (News Release 26-326, March 16, 2026)
- U.S. Consumer Product Safety Commission: Generator tips ahead of hurricane season (News Release 26-519, May 27, 2026)
All quotes above are from the USFA page. The two CPSC releases are further reading from another federal agency.
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