How often should you test your smoke and CO detectors?

This task protects people, not just the house. Do it on a schedule to make sure it gets done.

Staying on schedule matters beyond the repair bill: a consistent maintenance record is one of the factors in a home's Roots Home Health Score, and well-kept homes typically sell faster and closer to asking price.

How to do it

The test button checks the battery, horn, and circuit, which is where nearly all real-world failures live. Test monthly on a fixed cue, and know each unit's age: smoke sensors retire at 10 years, CO sensors at 5–10.

1. Press and hold the test button on every unit until the alarm sounds: every bedroom, hallway, and floor, including the basement.
2. Replace the battery in any unit that chirps, sounds weak, or is on a schedule (non-sealed units: yearly; pick a fixed date like the fall time change).
3. Vacuum each unit's vents. Dust is the top cause of false alarms and desensitized sensors.
4. Check the manufacture date on the back of each unit: replace smoke alarms at 10 years, CO alarms per the model's rating (5–10 years).
5. If units are interconnected, confirm one test triggers them all.

Alternatives & optional extras

• A yearly pass with the vacuum over each unit's vents prevents most false alarms.
• When replacing, sealed 10-year-battery models eliminate battery changes entirely.
• Interconnected (wired or smart) units trigger together. Worth it in multi-story homes.

Time: 10 minutes · Typical cost: Free; $10–$25 for batteries; ~$40–$70 per replacement combo unit

What you'll need

• Replacement batteries (long-life lithium batteries last years longer than alkaline)
• Combination smoke + CO detector (sealed 10-year battery)

If you skip it

This is the one task on the list where the downside isn't measured in dollars. Working detectors roughly halve the risk of dying in a home fire, and CO has no smell, color, or warning at all. An expired or dead unit removes the only alert you'd ever get.

Other smoke & co detectors maintenance

• Replace smoke detector batteries — once a year
• Replace smoke and CO detector units — every 10 years

Related systems to keep on schedule

• Fire extinguisher — start with: check fire extinguisher gauge and condition, once a year
• Security system — start with: test security system and camera batteries, every 6 months