Locksmith guide
Rekey or Replace? How to Decide
By Johnson Locksmith Inc. ·
Rekey when the hardware is sound and you only want the old keys to stop working, which covers most situations including moving into a new home. Replace when the lock is worn, damaged, or below the security grade the door needs. Rekeying is faster and costs less because you are buying labour and pins rather than hardware.
What rekeying actually does
Inside a standard cylinder is a row of spring loaded pin stacks, each split into a top and a bottom pin. The correct key lifts every stack to exactly the height where the split lines up with the edge of the plug, and only then can the plug turn.
Rekeying means pulling the plug, swapping the bottom pins for a different set of heights, and cutting a new key to match. The lock body, the finish, the strike, the screws and the door prep are all untouched.
From outside, nothing has changed. From inside, the old key no longer lifts the stacks correctly and will not turn. That is the whole point: in most situations what a homeowner actually wants is not new locks, it is for the previous keys to stop working.
The decision in one table
The question is whether the hardware itself is still doing its job.
| Rekey | Replace | |
|---|---|---|
| Old keys stop working | Yes | Yes |
| Keeps existing hardware and finish | Yes | No |
| Typical time per door | 10 to 20 minutes | 30 to 60 minutes |
| Relative cost | Lower | Higher |
| Fixes a worn or sticking lock | No | Yes |
| Upgrades the security grade | No | Yes |
| Puts several doors on one key | Yes, if keyways are compatible | Yes |
| Right after moving in | Usually | If the hardware is old or damaged |
When to rekey
The trigger is always the same underlying fact: a working key exists somewhere you cannot account for. That is a security problem regardless of who holds it.
- You have just taken possessionEvery closing hands over an unknown number of copies: agents, contractors, cleaners, the previous owner and their circle. Do it in the first week.
- A tenancy has endedStandard practice at every turnover. Note that under Ontario's Residential Tenancies Act a landlord may not change the locks during a tenancy without giving the tenant a key.
- A key has gone missingEspecially if the ring carried anything identifying the address, which in practice it usually does.
- A relationship or arrangement endedA separation, a former roommate, a caregiver who no longer works for you. This is the most common residential rekey call and needs no explanation.
- A renovation has finishedTrades often hold a construction key for months. Rekey the week the last contractor hands the site back.
- You want one key for the whole houseFront, side, garage and patio doors keyed alike, so a single key runs the property.
When replacing is genuinely the better spend
There is a clear line, and a good locksmith will point at it rather than sell you a rekey that will disappoint.
Replace when the plug is loose in the housing, which shows up as a key that wobbles noticeably when inserted. Repinning a worn shell just puts fresh pins into a cylinder that no longer holds tolerances.
Replace when the lock has been forced. A cylinder that has been drilled, snapped or pried has lost its security value even if it still turns.
Replace when the hardware is below the grade the door needs. A Grade 3 deadbolt on a front door was never adequate, and rekeying it just preserves an inadequate lock. If you are paying for a visit anyway, moving up a grade is the better use of the money.
And replace when parts are no longer made, which is common with hardware from the 1970s and 1980s.
The thing that matters more than either
Whichever you choose, the strike plate matters more than the cylinder does.
Most forced entries do not defeat the lock at all. Someone kicks the door and the strike plate, held by two short screws into soft trim, tears out with a section of the frame attached. The deadbolt is still locked, still perfect, and lying on the floor inside a hole.
A reinforced or box strike anchored with three inch screws that pass through the jamb and bite into the structural stud costs less than the deadbolt does and raises the force required to open the door enormously.
If you are booking a locksmith for a rekey or a replacement, add this to the job. It is the cheapest genuinely effective security upgrade available for a house, and it is the one almost everybody skips.
Frequently asked questions
Can locks from different brands be put on one key?
Can a Kwikset SmartKey lock be rekeyed?
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