Rekey or Replace Your Locks? How to Decide (San Jose, 2026)
TL;DR - Quick Answer
Rekeying changes the internal pins in your existing lock so old keys stop working — it's usually faster and less expensive than replacing hardware. Replacement makes more sense when the lock is old, damaged, doesn't match your other doors, or you want to upgrade to a smart lock or higher-security deadbolt. Most South Bay homeowners rekey after moving in or losing a key, and replace when the hardware itself is the problem. A locksmith can look at your actual locks and tell you which route fits your situation and budget.
What Rekeying Actually Does
Rekeying is a mechanical adjustment made inside your existing lock cylinder — the outside hardware, brand, and finish all stay exactly the same. A locksmith removes the cylinder, takes out the small spring-loaded pins that match your current key, and swaps them for a new set of pins cut to match a brand-new key. Once that's done, every key that used to open the lock — old copies, keys given to a previous tenant, keys a contractor may still have — simply stops working. Nothing about the lock's appearance, its grade, or how it's mounted on the door changes.
This is different from re-keying being confused with re-pinning tumblers on a whim; it's a precise process that requires the right pin kit for your specific lock brand (Kwikset, Schlage, Baldwin, and others all use slightly different pin sizes and cylinder designs). Because the hardware itself isn't touched, rekeying doesn't address a lock that's physically worn, loose, rusted, or has a damaged strike plate. It only solves the "who has a key" problem — which, for most people who call about their locks, is actually the real concern.
A common and convenient side benefit: if you have several different keyed locks around your home, a locksmith can often rekey all of them to open with one single key during the same visit. That's a separate decision (covered below), but it's frequently bundled with a standard rekey since the labor is already happening at your door.
When Rekeying Is the Right Call
Rekeying tends to be the more sensible choice in a handful of common situations:
Moving into a new home or apartment. You have no way of knowing how many keys exist for your new front door — previous owners, real estate agents, past tenants, neighbors who watered plants, or a cleaning crew may all have copies. Rekeying immediately after you get your keys is one of the most straightforward ways to start fresh without buying new hardware. This is true whether you're buying a house, closing on a condo, or picking up keys to a rental in San Jose or anywhere in the South Bay.
Losing a key or having one stolen. If a key goes missing — dropped somewhere, taken from a bag, or simply unaccounted for — rekeying invalidates that lost key without needing to replace the lock it opens. This is often faster peace of mind than wondering if it will turn up or worrying who might find it.
Ending a relationship with a roommate, tenant, or ex-partner. Landlords managing a turnover between tenants, or anyone who's had a roommate or partner move out, often rekey rather than replace so that person's key no longer works, while keeping the same hardware and look on the door.
After a contractor, house-sitter, or cleaning service has had a key. Even when there's no reason to suspect anything, some homeowners simply prefer a clean slate once outside access is no longer needed.
When the lock itself is in good shape. If the deadbolt and knob operate smoothly, the door isn't damaged, and you like the current hardware, there's often no reason to replace something that's mechanically sound. Rekeying lets you keep it while resetting who can get in.
When Replacement Makes More Sense
Rekeying only changes the pins — so if the problem is with the hardware itself, replacement is the better route:
The lock is old, stiff, or unreliable. Locks that stick, that require jiggling the key, or that have started to feel loose in the door are showing mechanical wear that rekeying can't fix. Worn cylinders and tired springs are a hardware issue.
There's visible damage. A lock that's been forced, pried, drilled, or otherwise tampered with — even if it still technically works — should generally be replaced rather than rekeyed, since the internal components or the strike area may no longer be sound.
You want a security upgrade. If your current deadbolt is a builder-grade basic model and you want something with a higher security rating, reinforced strike plate, or anti-pick/anti-bump features, that means new hardware, not new pins.
You're switching to smart locks or keypad entry. Moving to a keypad deadbolt, a smart lock with app or code access, or a lock that fits into a broader home security setup requires installing new hardware — rekeying an old mechanical lock doesn't get you there.
Mismatched or outdated hardware across the house. If your front door, back door, and side gate all use different brands or old, discontinued lock lines, replacement is often the more practical path toward getting everything on the same keyway so keyed-alike or master-key setups are possible later.
Fire or storm damage, or a remodel. If a door itself is being replaced or refinished, it usually makes sense to install fresh hardware to match rather than pulling an old lock off a new door.
In short: rekey when the concern is who has access; replace when the concern is the lock itself.
Keyed-Alike: One Key for Every Door
Many homes end up with a mismatched set of locks — a front door deadbolt from one manufacturer, a back door knob from another, maybe a side gate or shed with its own separate key. "Keyed-alike" simply means having a locksmith set up multiple locks so a single key opens all of them, which is a common request during a rekey or replacement visit.
This is different from a full "master key" system (more common in commercial or multi-unit settings, where a master key opens everything but individual keys only open specific doors). For a typical single-family home, keyed-alike is usually enough — one key for the front door, back door, and maybe a garage service door or gate.
The tradeoff worth knowing: because all those locks now share the same pin configuration, losing that one key means every keyed-alike lock is affected, not just one. Some homeowners prefer to keep at least one entry point on a separate key for that reason. It's worth mentioning this preference when a locksmith is out at your home so the setup matches how you actually want to manage access.
Keyed-alike work is often done at the same time as a rekey (matching existing hardware to one key) or during a replacement (installing new locks that are keyed alike from the start), so it rarely adds a separate visit — just a bit of extra time during the appointment.
Cost Comparison (Broad Ranges)
Pricing for lock work varies by the number of locks, the brand and complexity of the hardware, whether keyed-alike work is involved, and the specific circumstances of the job (a straightforward rekey versus one that also needs a damaged strike plate repaired, for example). As a general frame of reference for South Bay homes:
- Rekeying a single lock typically falls in a modest range — often less than replacing that same lock outright, since labor is the main cost and no new hardware is purchased.
- Rekeying multiple locks at once (keyed-alike) usually costs less per lock than rekeying them one at a time on separate visits, since it's bundled into a single trip.
- Replacing a standard deadbolt or knob costs more than rekeying that same lock, since it includes the price of new hardware plus installation labor.
- Upgrading to a smart lock or keypad deadbolt generally sits at the higher end, reflecting the cost of the hardware itself, which varies widely by brand and features.
These are broad, general ranges only — actual pricing depends on your specific locks, hardware choice, and the scope of the job, and should be confirmed directly with a locksmith before work begins. Get an exact quote by describing your locks and situation over the phone; it's the only reliable way to know what your particular job will cost.
How Long Each Takes
Rekeying is generally the quicker of the two jobs. Because it only involves swapping pins inside an existing cylinder, a single lock can often be rekeyed in well under an hour once a locksmith is on-site with the correct pin kit for your hardware brand. Rekeying several locks to be keyed-alike takes a bit longer per additional lock, but is still usually completed in one visit.
Replacement takes a bit more time, since it involves removing the old hardware entirely, potentially adjusting or repairing the door prep (the holes and mortises cut into the door), and installing and testing new hardware. A standard deadbolt or knob swap is still typically a same-visit job. Smart lock installation can take a little longer, especially if it needs batteries installed, an app paired, or codes programmed on-site.
For both rekeying and replacement, the actual time on any given visit depends on the number of locks, whether any doors need adjustment, and whether extra features like keyed-alike setup or smart lock programming are part of the job. A locksmith can give a realistic estimate once they know what your doors and locks look like — timing for any specific appointment is always confirmed directly by phone rather than promised in advance.
FAQ
What's the difference between rekeying and replacing locks?
Rekeying changes the internal pins inside your existing lock so old keys no longer work, while the hardware itself stays the same. Replacing means removing the old lock entirely and installing new hardware. Rekeying addresses "who has a key," while replacement addresses problems with the lock itself, like wear, damage, or wanting different features.
Should I rekey or replace locks after moving into a new home?
Most people rekey after moving in, since the existing locks are usually in fine working condition and the main concern is unknown copies of keys held by previous owners, agents, or past tenants. If the locks are old, damaged, or you want to upgrade features like a smart lock, replacement may make more sense instead.
How much does it cost to rekey a lock versus replace it?
Rekeying is typically less expensive than replacement, since it's mainly a labor cost with no new hardware to buy, while replacement includes both labor and the price of a new lock. Exact costs vary by the number of locks, hardware brand, and job specifics, so it's best to get a direct quote based on your situation.
Can all my locks be changed to use one key?
Yes, this is called keyed-alike, and it's a common request when rekeying or replacing multiple locks on the same property. A locksmith can set up your front door, back door, and other locks to share a single key, usually during the same visit as the rekey or replacement work.
Do I need to replace locks after losing a key?
Not necessarily — if the lock itself is in good working condition, rekeying it is usually enough to make the lost key useless without needing new hardware. Replacement is more relevant if the lock was already worn, damaged, or you want a different type of lock going forward.
Is rekeying good enough for security after a break-in attempt?
If a lock has been forced, drilled, or otherwise damaged during a break-in attempt, replacement is generally the better choice, since rekeying doesn't fix physical damage to the mechanism or the door itself. A locksmith can inspect the lock and door hardware on-site to advise whether it can be safely rekeyed or should be replaced.
How long does it take to rekey or replace a lock?
Rekeying a single lock is usually quicker, often completed in under an hour once a locksmith has the correct pins for your hardware. Replacement takes somewhat longer since it involves removing old hardware and installing and testing new hardware, though a standard swap is typically still a same-visit job.
Can landlords rekey between tenants instead of replacing locks?
Yes, rekeying between tenants is a common and practical approach as long as the existing locks are in good mechanical condition, since it resets access without the cost of new hardware. If locks are older, worn, or inconsistent across units, some landlords choose that transition point to replace and standardize hardware instead.
Last updated: August 2026