When's It DueHow often
How often should you replace a smoke alarm battery?
Every 12 months, and test when the clocks change
GOV.UK and Fire Kills use clocks-changing weekend as the cue to test every alarm. Most 9V backup cells are due about once a year, or at once if the test fails.
Signs it is worn out — save it nowSave one of these
Smoke alarm battery
Every year
Why replace it
An alarm that does not sound in a test cannot warn you at night. The battery is cheap; the gap is remembering.
Signs it is worn out
- The alarm chirps
- The test button is silent
- You cannot remember the last 9V swap
Source: GOV.UK: change your clock, test your smoke alarm. As an Amazon Associate I earn from qualifying purchases.
Also worth tracking
- How often should you replace toothbrush heads?Every 3 months
- How often should you replace electric toothbrush heads?Every 3 months
- How often should you replace a BRITA water filter?About every 4 weeks
- How often should you replace a fridge water filter?About every 6 months