12 Things to Change or Replace the Week You Move In

TL;DR: Rekey or replace every exterior lock in the first 48 hours after closing, since you have no idea how many spare keys are out there. In the same week, swap the HVAC filter, test every smoke and carbon monoxide detector, reset the garage code, and locate the main water shutoff. Most of these 12 tasks cost under $50 each and take 20 minutes or less.

_Last reviewed: August 2026 · 8 min read_

The old owner is gone, but their keys, codes, and habits are still baked into the house. Locks were copied for a dog walker three owners back. The furnace filter hasn't been touched since the listing photos were staged. Here's the exact list to work through in your first seven days, in order of what actually matters first.

Okoniq Property Hub keeps a running log of every move-in task, date completed, and receipt, so you're not guessing a year later whether that filter ever got changed.

Which locks and entry points should you change first?

Every exterior lock, full stop, within the first two days. Rekeying a standard deadbolt costs $15–$25 per lock in parts if you do it yourself with a rekey kit matched to the existing pins, or $75–$150 per lock if you call a locksmith for the whole house. A full lock replacement with new hardware runs $40–$120 per door.

Don't stop at the front door. Change the garage door keypad code and any smart lock PIN immediately, since those are often left at factory defaults or shared with a cleaning service. If there's a shed, gate, or mailbox with its own lock, do those too. Sellers rarely track every copy they've handed out over the years to contractors, dog sitters, and former tenants, and you have no way to verify how many exist. If your purchase included a home inspection contingency, the report may note whether locks were part of the negotiated repairs, but that's separate from simple rekeying, which is on you.

What safety devices need fresh batteries or full replacement?

Smoke detectors and carbon monoxide alarms need new batteries the day you move in, and full unit replacement if they're older than 10 years. Check the manufacture date printed on the back; most units have a hard expiration even with battery swaps, and 10 years is the standard life for photoelectric smoke detectors under NFPA guidelines. A basic replacement unit runs $10–$25, and combo smoke/CO units run $30–$50.

While you're at it, test the fire extinguisher gauge (replace if the needle sits outside the green zone) and check that every window has a working lock and, on upper floors, a fire escape ladder if the house doesn't have a second exit. If you're pulling out your home inspection report from closing, cross-reference it against what you find, since inspectors sometimes flag detector age or missing units that get lost in the pile of paperwork during closing week.

Which filters and mechanical items should you swap right away?

The HVAC filter, water filter, and any humidifier pad should all be replaced in week one, regardless of what the seller told you. A standard 1-inch HVAC filter costs $8–$20 and takes five minutes; a whole-house water filter cartridge runs $20–$60 depending on the system. You have no reliable way to know the last time either was touched, and a clogged filter strains the furnace or AC compressor within the first season of ownership.

Also swap the shower heads and any exposed sink aerators if the home is more than 10 years old — mineral buildup is common and a $10 shower head fixes water pressure complaints instantly. Locate and test the main water shutoff valve and the electrical panel breakers now, before an emergency forces you to find them at 11 p.m.

| Item | Typical Cost | Time to Replace | |---|---|---| | HVAC filter | $8–$20 | 5 minutes | | Water filter cartridge | $20–$60 | 15 minutes | | Smoke/CO detector | $10–$50 each | 10 minutes each |

What paperwork and settings need updating before you settle in?

Update the address on your insurance policy, change the thermostat schedule, and re-register any smart home devices under your own account, not the seller's. Ring doorbells, smart thermostats, and garage systems often stay logged into the previous owner's app unless you explicitly transfer or factory-reset them, which means they could technically still see your camera feed or control your garage.

Pull your closing documents and confirm what's covered under any home warranty that came with the sale, since many run 12 months from closing and cover appliance or system failures you'd otherwise pay for out of pocket. Check your closing costs statement for any prorated utility or HOA fees that need a follow-up call in the first week, and set a reminder for any warranty registration deadlines, which are often 30–60 days from closing.

Do you need to worry about anything the inspection might have missed?

Yes, walk the property again with fresh eyes once furniture is out of the way. Movers moving heavy items sometimes reveal hairline cracks, water stains, or outlet issues that weren't visible during a staged showing. If you're a landlord bringing in a tenant right behind your own move, the same discipline applies at turnover — sloppy documentation is one of the inspection mistakes that cost the deposit fight later, so photograph everything before anyone unpacks a single box.

FAQ

How much does it cost to change all the locks in a house?

Rekeying a typical 3-bedroom house with 3–4 exterior locks costs $60–$400 total, depending on whether you do it yourself with a rekey kit or hire a locksmith for full replacement.

Do I really need to replace smoke detectors if they're working?

Yes if they're over 10 years old, even if the alarm still sounds during a test. The sensor inside degrades with age and can fail to detect smoke reliably well before the unit stops beeping entirely.

Should I change the garage door code even with a physical key backup?

Yes, reset it the day you get keys. Garage keypad codes are commonly shared with contractors, cleaners, and neighbors over the years and are one of the easiest entry points to overlook.

How soon after moving in should I change the HVAC filter?

Within the first week, regardless of what the seller claims. A $10–$20 filter is cheap insurance against strain on a furnace or AC system you haven't had time to fully evaluate yet.

What's the single most overlooked item on a move-in checklist?

Re-registering smart home devices under your own account. Ring cameras, smart thermostats, and garage systems often stay tied to the previous owner's login unless manually reset, leaving a real privacy gap.

This is educational information, not safety or legal advice. Call a licensed locksmith, electrician, or HVAC technician if you're unsure about any repair or replacement on this list.