Moved into a new home? Your lock checklist

Why change the locks after you move in?

Because you can't know how many keys and codes are out there. A rekey on move-in day turns all of them off at once.

Keys collect over the years. Think about who may still hold one to the house you just moved into:

• The previous owners, and their grown children, parents or friends.
• Earlier tenants, if the house was ever rented.
• Cleaners, dog walkers, babysitters and home health aides.
• Contractors who worked on the house while it was for sale.
• Neighbors who watered the plants.
• Anyone who knew where the spare under the mat was.

Most of these people mean no harm. The point is that you can't ask them all to give keys back, and you can't tell which copies are still around. A rekey, or new locks, ends the question.

Should you rekey or replace on move-in day?

Rekey the locks that work well, and replace any that are worn, damaged or weaker than you want. Many people do a mix.

If the locks turn smoothly and you like them, a rekey is quicker and keeps the hardware. If the front deadbolt sticks, the back door has only a knob, or you want a keypad, replace those. Our guide to rekeying or replacing locks walks through the choice, including how to get one key for every door.

Door by door: what should you check?

Every door that leads outside or into the garage, plus the patio door and any gates. Walk them all once with this list.

Front door

• A deadbolt as well as the knob or lever. The bolt should slide all the way out without pushing on the door.
• The deadbolt locks with a key outside and a thumb turn inside.
• The strike plate on the frame has long screws (see below).
• Hinges on the outside have pins that can't simply be lifted out.

Back and side doors

• The same checks as the front. Back doors are often the weakest door in the house and the least looked at.
• Glass next to or in the door: a thumb turn within reach of a broken pane is a known weakness.

The door from the garage into the house

• It is easy to forget, and it is a real outside door when the garage is open.
• Give it a deadbolt and put it on the same key as the rest.

Sliding glass doors

• Check the latch catches every time. Older latches wear and stop catching.
• Add a bar or a length of dowel in the bottom track so the door can't slide even if the latch fails.

Gates, sheds and outbuildings

• Padlocks left by the old owner: cut them off and use your own.
• A side gate with a combination lock: change the combination.

What about the garage door opener?

Treat every old remote as a house key. Clear all stored remotes from the opener, change the keypad code, and set up only the remotes and cars you own.

Most openers can erase every remote they have learned. The steps differ by brand, and they are in the opener's manual or on the maker's support pages; the model number is on a label on the motor unit. After you erase, add back the remotes you were handed, your own car's built-in opener if it has one, and nothing else.

Then the outside keypad. Change its code. If the opener connects to an app, remove the previous owner's account from it, or reset the opener's connection and set it up again under your own account.

How do you reset keypad and smart locks?

Do a factory reset, delete every user code, and make sure no one else is an owner or admin in the lock's app. Then set it up fresh under your own account.

• Factory reset. Most smart locks and keypad locks have a reset button or procedure in the manual. A reset clears stored codes and app links.
• New codes. Avoid birthdays, house numbers and repeating digits.
• Your own account. Use a strong, unique password and turn on two-step sign-in if the app offers it. CISA, the US cybersecurity agency, recommends strong unique passwords with a password manager (CISA on passwords) and turning on multifactor authentication (CISA on MFA).
• The key backup. Many smart locks still have a key cylinder. Rekey it too, or the old owner's key may still open the door.
• Video doorbells and cameras. The same applies: reset them and remove old accounts.

If you are thinking about adding a smart lock, read our smart lock pros and cons first.

Do the strike plates have long screws?

Check them. A strike plate fixed with short screws only holds in the thin door frame, and a hard kick can split the frame even when the lock holds.

The strike plate is the metal plate on the door frame that the bolt slides into. Behind the thin wooden jamb there is a gap, then the framing of the wall. Short screws stop in the jamb. Longer screws, often around three inches, reach through into the framing and make the door far harder to force.

Take out one screw and look at its length. If it is short, replace each one with a longer screw. Do the same for at least one screw in each hinge on the frame side. It is one of the cheapest upgrades in the house. BHMA's consumer ratings site, Secure Home, is a good place to compare locks if you are replacing any.

What about the windows?

Every window should close fully and its latch should catch. Ground-floor windows and windows you can reach from a deck or porch roof matter most.

• Test each latch. Painted-over latches and bent ones are common in older houses.
• Look for missing latches or windows that were screwed shut and later opened.
• Window units for air conditioning can make a window easy to open from outside; check how they are secured.

What else uses a key or a code?

More than people expect: mailboxes, alarm systems, gates, pools and lock boxes. List them all in the first week.

• Alarm system. Change the codes, and contact the monitoring company to put the account in your name, or cancel it.
• Mailbox. Cluster mailboxes in neighborhoods and apartment buildings are often handled by the post office or the property manager, not a locksmith. Ask them how to get new keys.
• Neighborhood gates, pool and gym fobs. Ask the HOA to cancel the previous owner's fobs and issue new ones.
• Agent lock boxes. Make sure the box used during the sale is gone, along with the key inside.
• Hidden spares. Check under mats, planters, fake rocks and the top of the door frame.

What order should you do it in?

Locks and openers first, because they control who can walk in. Codes, accounts and smaller items can follow over the first week.

1. Day one: rekey or replace every outside lock, including the garage entry door. Get enough keys for the household.
2. Day one: erase all garage remotes and change the keypad code.
3. Day one: factory reset any smart lock or keypad and set it up under your own account.
4. First week: longer strike and hinge screws, a bar in the patio door track, a check of every window latch.
5. First week: alarm codes and account, HOA fobs, mailbox keys, any padlocks.
6. Keep a list of who you give a key or code to. It makes the next change easy.

Renting a new place?

Ask the landlord, don't change locks yourself. Most leases require written permission, and the landlord needs a working key for repairs and emergencies.

It is fair to ask whether the locks were rekeyed after the last tenant moved out. Many managers rekey between tenants as a matter of course. If they didn't, ask them to, or ask in writing for permission to have it done and to give them a key. The key control guide for landlords covers what a well-run turnover looks like from their side.