What does it cost to hire out "Test every detector — day one"?

A fair national range is $100–$250; local labor costs move that number up or down by county.

How often should this be done?

Once is enough — it's a one-time job.

What should I ask before hiring someone for this?

Worth asking: Can you swap all of these for interconnected units so they alarm together? Are we covered per code — one in each bedroom, one outside each sleeping area, one per floor?

How do I know I'm being upsold on this job?

Watch for: A 'monitored fire system' pitch when what you need is $100 of detectors from the hardware store. Per-detector install pricing over $50 a unit for battery models — it's a step stool and two screws.

Settling in

Test every detector — day one

One-time · any month works

Why it matters

You don't know when these detectors were tested, how old they are, or whether the sellers' painter took the batteries out in 2019 and never confessed. Day one of ownership is the reset: every detector proven working, every expired unit gone.

Detectors expire — the sensors wear out. Smoke units die at 10 years, CO units at 5 to 10 depending on model, and an expired detector with a happy green light is the most dangerous object in the house because it looks like protection.

What skipping it costs

$0–$30

The dollar cost is a detector or two. The real cost is the one statistic that matters: most fatal home fires happen in homes where detectors were missing, dead, or expired. The sellers' detectors are of unknown age with unknown batteries — treat them as guilty until proven working.

Two ways to get it done

Do it yourself

~30 min · difficulty 1 of 5

You'll need: A step stool, Your phone camera, 9V or AA batteries for any that complain, Replacement detectors for any past 10 years (~$15–$30 each).

Walk every room. Code coverage is: one smoke detector inside each bedroom, one outside each sleeping area, one per floor including the basement. Note the gaps.
Press and hold the test button on every unit until it screams. No scream, or a weak one — new battery, then retest. Still nothing — replace the unit.
Flip each one off its bracket and read the manufacture date on the back. Past 10 years (5–7 for some CO models): replace, today, no sentimentality.
Photograph the dates you're keeping so future-you knows when they age out — the app's recurring detector check takes it from here twice a year.
Buying replacements: sealed 10-year-battery smoke units end the battery-chirp era entirely, and combo smoke/CO units simplify coverage.

Hire it out

$100–$250National fair range — local labor moves this number.

There's nothing here that needs a pro — but if you'd rather hand it off, an electrician or handyman will audit and replace the lot for $100–$250 plus hardware. The one genuinely worthwhile upgrade to ask about: interconnected detectors (wired or wireless-linked), so a basement alarm wakes the upstairs bedrooms. If the house already has wired interconnect, replacements must match it — that's a legitimate reason to let a pro handle the swap.

Ask the tech

Can you swap all of these for interconnected units so they alarm together?
Are we covered per code — one in each bedroom, one outside each sleeping area, one per floor?

Red flags you're being upsold

A 'monitored fire system' pitch when what you need is $100 of detectors from the hardware store.
Per-detector install pricing over $50 a unit for battery models — it's a step stool and two screws.

The call

DIY, before your first night if you can. Press every button, read every date, and replace anything over 10 years old without debate.