The short answer
Rekey every exterior lock in your first week. Not because anybody did anything wrong, but because the number of keys in existence for that house is genuinely unknown, to you and to the seller equally.
Rekeying changes the pins inside the cylinders you already own so a new key works and every previous key stops. The hardware stays on the door. It is far cheaper than replacement and it achieves the identical security outcome.
Walk the property and count exterior doors before you call. The number is almost always higher than the one in your head. Front, back, side, kitchen, garage entry, cellar, shed, gate.
And ask for reinforced strike plates on the same visit. Three-inch screws into the framing rather than three-quarter-inch screws into trim. It costs very little added to a rekey and on most Delaware housing it is worth more than the lock itself.
The long answer
Why the key count is unknowable.
This is not a suspicion about anyone. It is arithmetic about how houses actually work.
Think about the last house you lived in for several years. A key went to a relative for a week and came back, or did not. A cleaner had one. A dog walker had one. A contractor doing a bathroom had one for a fortnight. A neighbour watered the plants during a holiday. An agent's lockbox held one during the sale, and every viewing agent had the code.
None of that is unusual and none of it is careless. It is simply what happens over years of living somewhere. What does not happen is anybody keeping a register. So when a seller hands over three keys in good faith, they are handing over the three they know about, and their honest belief that those are all of them is not evidence.
Now add the previous owner before them, and the one before that. On an older Delaware house, a Wilmington row home, an Elsmere twin, a Wyoming or Milford house that has changed hands six times, keys have been cut over decades by people nobody can now name. Some of those keys still exist in drawers all over the state.
The point is not that somebody is coming. Overwhelmingly nobody is. The point is that you cannot demonstrate otherwise, and the cost of removing the uncertainty is one short visit at a price that is trivial next to what you have just spent on the house.
New builds have a different version of the same problem and people assume they are exempt. Builders frequently key an entire construction phase alike so trades can move between houses without a bunch of keys, with the intention of rekeying each property at handover. Sometimes that step is skipped. Sometimes it is done for part of a phase. The test costs nothing: ask a neighbour on your phase to try their front door key in yours.
The last piece is scope. People think about the front door because that is the door they picture. The keys opened more than the front door, and the garage entry, unheated, unweatherproofed, cheapest lock on the property, behind a garage door that is often the easiest way in, is the one that gets missed.
Your first week
In priority order.
| Do this | Why | When |
|---|---|---|
| Count every exterior door | A rekey that misses a door has achieved nothing, every old key still opens the house | Before you call |
| Rekey all of them, one visit | Batching is dramatically cheaper per lock than discovering the fourth door next month | First week |
| Reinforced strikes, 3-inch screws | Where a Delaware door actually fails. Nearly free during an existing visit | Same visit |
| Deadbolt anywhere there is only a knob lock | A knob lock is a spring latch with a keyway. Common as the only lock on post-war housing | Same visit |
| Check the garage-entry door | Weakest lock on the property behind the easiest entry. Consistently forgotten | Same visit |
| On a new build, try a neighbour's key | Construction phases are often keyed alike and not always reset at closing | First week, costs nothing |
| Change any keypad or smart-lock codes | Installer defaults and previous owner codes persist through a sale | Day one |
| Patio and slider hardware | The factory latch on an older aluminum slider gives up under a shoulder | First month |
| Decide on keying alike | People lock the doors that are easy to lock. Cheap now, expensive later | Mention when you book |
Before you call
Five minutes that make the quote accurate.
- Walk the outside of the house and count. Every door to outdoors or to an unheated space. Write the number down rather than estimating on the phone.
- Try each key in each lock. If one key already opens front and back, those cylinders share a keyway and keying the rest alike is straightforward.
- Pull one strike plate. Three-quarters of an inch means every exterior door has the same weakness and it is an hour's work to fix all of them.
- Note anything that binds. A door that needs lifting or shouldering is an alignment problem, not a lock problem. Say so when you call, it changes what gets brought.
- Look for hardware that is old rather than tired. Good old brass is worth keeping and rekeying. Cheap old hardware is worth replacing. We will tell you which is which rather than condemning it on sight.
- Find the codes. Alarm panel, garage door opener, any keypad. Installer defaults and previous owner codes survive a sale, and changing them costs nothing.
- Book it as one appointment. Travel and set-up happen once. This is the single biggest lever you have on the price.
Cost
What decides the number.
| Factor | Effect |
|---|---|
| How many cylinders | The biggest factor and the one you control. Every lock after the first on the same visit costs substantially less. |
| Rekey or replace | Rekeying reuses hardware you already own. Replacement only where the hardware is genuinely worn or inadequate. |
| Type of hardware | Standard residential, mortise, multipoint and high-security are four different jobs with four different parts. |
| Keying alike | Small addition during a rekey if the cylinders share a keyway; a swap where they do not. |
| Strikes and deadbolts on the same visit | Very little added to work already happening. A separate call-out later costs many times more. |
| Booked or urgent | A move is planned work. Book it for a weekday and it costs less than an out-of-hours call. |
| Access | A house full of boxes with a door blocked, or a gate needing a ladder, adds time. Clear the doors before we arrive. |
The one thing to ask for by name
Say: "rekey every exterior door, key them alike, and fit reinforced strikes with three-inch screws."
That sentence covers the whole first-week job in one booking, gets you the batch price rather than three separate visits, and includes the upgrade that most improves a Delaware house, the one that almost never gets mentioned because there is no product to sell with it.
Delaware specifics
What you'll find, by where you've bought.
Wilmington, Elsmere, New Castle, Wyoming, Milford. Expect old doors and often mortise locks, the heavy rectangular case set into the door edge rather than bored through the face. These are usually rekeyed or rebuilt rather than replaced, and replacement means new door prep on a very old door. Expect also more exterior doors than a modern house: a side entrance, a summer-kitchen door, a cellar hatch, several of which have not been opened in years but still have working locks on them.
Brookside, Wilmington Manor, Bear, Collins Park. Post-war housing where a great many front doors carry a knob lock and no deadbolt at all. Rekeying a knob lock is rekeying a spring latch. The deadbolt and the strike are the point here, not the pinning, and the strike screws in this era of framing are always short.
Middletown, Townsend, Cheswold and the new subdivisions. Sound modern framing, builder-grade hardware, and strike screws that are still three-quarters of an inch because that is what comes in the box. Also the phase-keying question, which is worth five minutes to answer definitively.
Camden, Dover, Wyoming, Dover Base Housing area. If you are arriving on a PCS move, rekey in the first week whether you have bought or you are renting, with the landlord's agreement if renting, which they will normally give. You have no history with the property and no way of knowing how many keys exist after previous tenants and their families. It is one of the few things that can actually be settled quickly during a move where nothing else is.
Hockessin and Greenville. Often high-security cylinders and multipoint entry doors. Rekeying is possible but involves restricted components and proof of entitlement, which takes longer for exactly the reason you paid for it. Larger properties here also mean more locked things than doors, outbuildings, pool houses, gates, and that is a case for a documented keying plan rather than a bunch of unmarked keys.
One thing people forget on moving day
The garage side door. It is the entry almost nobody thinks about, it very often has the weakest lock in the house on it, and on a great many properties it leads straight into the kitchen through a door that is left unlocked. If you rekey nothing else on day one, rekey that one, and check whether the overhead door's emergency release cord can be reached from outside through the top of the frame.
Related
The decisions inside this one.
Rekey versus replace goes deeper on the choice, and the frame guide explains why the strike matters more than the lock.
Lock Rekeying
Every exterior door, keyed alike, in one visit.
SecurityDeadbolt Installation
Where a door has only a knob lock, with a reinforced strike as standard.
UpgradeLock Replacement
Where hardware is genuinely worn rather than simply old.
RepairLock Repair
For the door that binds and needs lifting rather than a new lock.
ElectronicSmart Lock Installation
If you want keypad access, after the frame is sorted, not before.
All home workResidential Locksmith
The full picture on locks at home across both counties.
Where we do this
New-home rekeys across both counties.
Questions
About locks in a new home.
How soon should I rekey after closing?
The first week, before you have unpacked properly. It is inexpensive, it takes one visit, and it closes the one gap you cannot see: the unknown number of keys that exist to a house that was somebody else's until recently. Everything else on a moving-in list can wait a month. This one is worth doing while the boxes are still in the hall.
The seller gave me all the keys. Isn't that enough?
It is not, and it is not a question about the seller's honesty. They cannot tell you how many keys exist either. Over a typical ownership, copies go to relatives, cleaners, dog walkers, contractors, house-sitters, an agent's lockbox and a neighbour who was watering plants. Nobody keeps a register. A handover of three keys is a handover of the three keys they know about.
How do I know how many exterior doors I have?
Walk the outside of the house and count doors that open to outdoors or to an unheated space. Front, back, side, kitchen, garage entry, cellar hatch, shed, gate. Owners routinely tell us two and we find four, the side door nobody uses and the garage entry are the two that get forgotten, and the garage entry is usually the weakest lock on the property.
Our subdivision is new. Do we still need this?
Yes, and possibly more urgently. Builders commonly key a construction phase alike so trades can move between houses, intending to rekey each at closing. That step gets skipped or half-done more often than anyone admits. Ask a neighbour on your phase to try their front door key in your door. If it turns, nobody did anything wrong, but you want it rekeyed that week.
Can I do the locks myself to save money?
You can change hardware yourself if you match backset, bore diameter, faceplate size and door thickness. Two things catch people: a lock that nearly fits binds, and the strike plate almost always gets reused with its original three-quarter-inch screws, which leaves a good lock on a weak frame. If you do it yourself, put three-inch screws into the framing behind the jamb. That detail matters more than which lock you buy.
Should I get all the doors on one key?
Usually yes, and the reason is behavioural rather than technical. People lock the doors they can lock easily. If the side door and the garage entry need a different key that lives somewhere else, those doors get left unlocked, and they are the ones nobody can see from the street. Keying alike is a small addition during a rekey and expensive as a separate visit later.
What if the house has old mortise locks?
Common in Wilmington, Elsmere, New Castle and the older Kent County towns, and usually good news. Mortise locks were built to be serviced and can normally be rekeyed or rebuilt rather than replaced. Replacement means new door prep on a door that may be a century old, which is more disruptive and more expensive than most people are told. Anyone quoting a replacement on sight probably does not carry mortise parts.
Is there anything else worth doing on the same visit?
Two things, and both are nearly free while a technician is already at your door. Reinforced strike plates with three-inch screws into the framing on every exterior door. And a proper deadbolt anywhere the door only has a knob lock, which on Delaware's post-war housing is a lot of front doors. Asked for during a rekey, both cost very little. Asked for later, you are paying for another call-out.
Walking the property before you change anything
A good first step after moving in is a slow walk through the whole property. Go door by door, including the front, back, garage, basement, patio and any side entrance. Note the type of lock on each one, whether it is a deadbolt, a handle set, a keypad or a basic knob, and whether the doors close and latch properly. Check windows with locks, sliding doors and their bars, and any gates. Make a simple list. This is more helpful than it sounds, because it lets the technician see the whole picture rather than guessing, and it prevents the surprise of finding a forgotten door later.
Collect every key you were given and test each one in each lock. You will often find keys that no longer match anything, keys that work on only one door, and doors that nobody gave you a key for at all. Mark them with tape or tags in a way that does not name the address. If a previous owner mentions garage openers, alarm codes or smart devices, change those codes too. A lock change is only part of the picture, because a code known to a former tenant is as much of a risk as a key they might still have.
Think about how your household will actually live in the house. Who needs a key, who comes and goes at odd hours, and who would prefer a keypad over a metal key? Decide how many copies you want and where the spare will be kept. Think about children, caregivers, dog walkers and delivery arrangements. This planning saves time on the day of the visit and often reduces the number of keys cut. We confirm availability by phone for your address, and explain the scope and any quote before work begins.
Rekeying a whole house so one key does everything
One of the most appreciated improvements in a new home is having a single key that works at every door. Previous owners often leave a patchwork, with a different key for the front, the back and the garage, and carrying four keys when one would do is a daily annoyance. A technician can often rekey several locks to match, provided the hardware uses compatible keyways. Where brands differ, one lock may need swapping for a compatible one. This is a straightforward job in most cases, but the details depend on what is installed, so the visit starts with an inspection of every lock involved.
The process works lock by lock. The technician removes each cylinder, replaces the internal pins with a new combination and reassembles it, then tests the key repeatedly. If a cylinder is worn or damaged, it may be replaced instead. Meanwhile the technician checks the deadbolt throw, the strike plate and any loose screws, because a new key in a loose lock is a weak result. Expect the work to be explained as it goes, and ask questions. If you want the main entry to carry better hardware than the rest, say so, and the tradeoffs can be described.
Before the visit, empty the area around each door so access is simple, and have all current keys together. Decide whether a few doors should stay on separate keys, such as a rented basement apartment or a shared workshop. Plan for the winter and summer cycles too, since wooden doors move with humidity and a freshly rekeyed lock may need an alignment tweak once the weather changes. The scope and any quote are explained before work begins, and you can ask the technician to recheck the lock after a few days of normal use.