New Home? The 24-Hour Lock Checklist

Rekey first, unpack later

Here is the uncomfortable truth about a house you just bought: you have no idea how many working keys exist. The previous owners made copies for their kids, a neighbor, a dog walker, a cleaner, a contractor who never gave one back. There was probably a realtor lockbox on the front door for weeks. Somebody's ex may still have one in a drawer. The three keys handed to you at closing are not an inventory of copies, they are just the three keys that happened to be lying around.

Rekeying fixes this without touching your doors. A locksmith pulls the cylinder, changes the pin stack inside, and cuts you new keys. Every old key stops working that afternoon. A whole-home rekey typically runs $225 to $375 depending on how many doors you have and what kind of locks are on them, and single cylinders usually run $30 to $60 each plus a trip fee of $75 to $150. Replacing every exterior lock with decent hardware and paying for installation is more like $600 to $1,500 for the same end result.

Replacement is worth the money in a few specific cases: the hardware is rusted, loose, or grinding; your locks are a mix of brands and keyways so they cannot be keyed alike; a main entry has thin builder-grade hardware you were going to upgrade anyway; or you want a smart lock. Otherwise, if the locks work smoothly, rekey them and put the difference toward better screws and a better front door deadbolt.

Walk the perimeter with a notepad

Before you call anyone, do one slow lap of the property in daylight and write down every lock you own. People consistently forget the door from the garage into the house. In a lot of American homes it is a hollow interior knob with no deadbolt at all, which means the only real barrier between the street and your kitchen is a garage door that opens with a remote. That door deserves a proper deadbolt more than almost any other door in the house.

Count the doors, then count the things that lock but are not doors. Note the brand stamped on each lock face, because matching brands and keyways is what lets a locksmith key everything alike so you carry one key instead of five. Take a photo of each lock with your phone. When you call for a quote, that list is the difference between a real price and a guess.

• Front door, back door, and any side or basement walk-out door
• The door from the garage into the house (add a deadbolt if there isn't one)
• The garage service door, the one on the side that opens to the yard
• Side and back gates, plus the shed or detached workshop
• Any storm door or screen door with its own latch
• Crawlspace, cellar, or bulkhead doors
• Note the brand and keyway on each lock so they can be keyed alike

Look at what hardware you actually inherited

Locks are graded by ANSI/BHMA on a 1 to 3 scale. Grade 1 is commercial strength, Grade 2 is solid residential, Grade 3 is the basic builder pack that comes on a lot of new construction. You will usually find the grade on the box, in the product listing, or stamped on the lock itself. If your main entry is Grade 3, upgrading that one deadbolt to a Grade 1 or 2 is a reasonable spend, and store hardware for that runs roughly $40 to $90 before installation.

Now do the cheapest real security upgrade available to a homeowner. Open your front door and look at the strike plate, the metal piece on the frame where the bolt lands. In most houses it is held by two short screws that bite into nothing but soft trim. Doors that get kicked in usually fail right there, at the jamb, not at the lock. Replace those with 3-inch screws that reach past the trim into the structural framing behind it. A box of screws costs a few dollars and the job takes ten minutes with a screwdriver.

While you are there, swap one screw in each door hinge for a 3-inch screw as well, and consider a box strike, which is a heavier strike plate with a metal cup behind it. None of this is glamorous and none of it shows. It is still the best security-per-dollar move in the house.

Smart locks, garage remotes, and codes

If the house came with a smart lock, assume the previous owner still owns it. Their phone may still be the admin account, their guest codes may still work, and their app may still show when your door opens. Factory reset the lock, create a fresh account in your name, delete every existing user code, and set new ones. Then remember the physical key override on the bottom of most smart deadbolts, because that cylinder is a normal lock and old keys still turn it. Have it rekeyed with the rest.

The garage opener is the same problem in a different box. Clear all paired remotes from the opener unit and re-pair only the ones you actually hold, then change the exterior keypad code. If you are not sure how, the model number and a search usually gets you there in five minutes, and any locksmith or garage tech can do it on a visit. Older openers that use a fixed code rather than rolling code are worth replacing outright.

Keep a short list of everyone who now has access, including any code you give to a cleaner, a sitter, or a delivery service. Most smart locks let you issue a separate code per person, and separate codes mean you can revoke one without changing everything.

Mailbox, HOA keys, windows, and sliders

Physical keys hide in odd places. Check the mailbox: if it is a curbside box with its own lock, rekey or replace it, because mail is where identity theft starts. If you are on a USPS cluster box, the Postal Service controls that lock, not you, so contact your local post office to have the key changed rather than calling a locksmith. Then ask your HOA or property manager to deactivate the previous owner's pool fobs, gym cards, gate clickers, and amenity keys and issue you fresh ones.

Windows are usually the weakest opening in a house and the least inspected. Test every sash lock, especially on ground floor and basement windows, and replace any that spin loose or do not seat. On sliding glass doors, the factory latch is often a thin hook. Add a bar or a cut dowel in the track, and put a couple of screws into the top track so the panel cannot be lifted out of its rollers. If there is a pet door big enough for a person's shoulders, treat it as a door.

If you're renting, do this instead

Renters have the same problem and less freedom. Many leases require the landlord to rekey between tenants, so the first move is to ask, in writing, whether that was done for your unit. Rules vary by state and by lease, but a written request to rekey for safety is reasonable and most landlords say yes, particularly if you offer to cover the cost and hand them a copy of the new key right away. A landlord generally cannot leave you locked out of your own unit, and they generally can require that they keep access.

Do not drill, do not swap hardware, and do not change anything without written permission. If you do replace a cylinder or add a lock, keep the original hardware in a labeled bag in a closet and reinstall it before you move out. That single habit is the difference between getting your deposit back and arguing about it. Renters can still do the free and reversible things: 3-inch strike screws, a bar in the slider track, window latches tested, and a doorstop alarm for a bedroom.

Your first-24-hours checklist

Run this list in one afternoon. Most of it costs nothing, and the parts that cost money are the parts that matter. If you are calling a locksmith, group the work into one visit so you pay one trip charge instead of three, and get the price in writing before anyone starts drilling anything.

• Rekey every exterior lock, including the garage-to-house door and any smart lock's key override
• Ask the locksmith to key everything alike where the hardware allows it
• Install 3-inch screws in every exterior strike plate and one per hinge
• Add a deadbolt to the garage-to-house door if it only has a knob
• Factory reset any smart lock, delete all old codes, create your own account
• Erase and re-pair garage remotes; change the garage keypad code
• Rekey or replace the curbside mailbox, or contact the post office for a cluster box
• Have the HOA deactivate old fobs, gate clickers, and amenity keys
• Test every window latch; add a bar and anti-lift screws to sliding doors
• Photograph your new keys' locations and note who has which code
• Renters: request rekeying in writing, and save the original hardware for move-out