Rekeying changes the internal pins in your existing lock so old keys stop working, while replacement swaps in a whole new lock body or brand. Rekeying is usually the right call after a move-in, a lost key, or a tenant change — as long as your current locks are in good working condition. Replacement makes more sense when hardware is worn, damaged, mismatched, or you want to upgrade to smart locks or better security grades. A locksmith can look at your specific doors and tell you which path actually fits, since "it depends" is genuinely true here.
If you've just moved into a South Bay home, lost a keychain, or had a roommate move out, you're probably asking yourself whether you need brand-new locks or just a key change. Both options get you to the same end result — old keys no longer open your doors — but they differ quite a bit in cost, time, and what they actually fix. Here's how to think it through before you call anyone.
Rekeying is a mechanical adjustment inside your existing lock, not a swap of the lock itself. Every pin tumbler lock uses a set of small pins cut to match a specific key. During a rekey, a locksmith removes the lock cylinder, takes out the old pins, and replaces them with a new set sized to a new key. The exterior hardware — the knob, deadbolt, or lever you see and touch every day — stays exactly the same.
Because the housing and mechanism aren't replaced, rekeying only works if the lock itself is in decent shape. A rekey doesn't fix a worn-out latch, a deadbolt that sticks, weather damage, or a cylinder that's been drilled or forced. It also doesn't upgrade the security level of the lock — if you had a basic hardware-store deadbolt, you'll still have one after rekeying, just with new pins inside it.
The appeal of rekeying is that it solves the actual problem most people have — "someone else might have a key" — without touching anything else about the door. It's typically the faster, lower-cost route when the hardware is sound, which is why it's the default recommendation for most move-ins and lost-key situations across San Jose and the South Bay.
There are a few situations where rekeying is almost always the sensible choice, assuming your locks are functioning normally:
Moving into a new home or apartment. You have no idea how many copies of the keys exist — previous owners, past tenants, cleaners, contractors, real estate agents, and neighbors who watered plants may all have one. Rekeying every exterior lock as soon as you get the keys is one of the simplest security steps a new resident can take, and in most cases the existing hardware is perfectly fine to keep.
Lost or stolen keys. If a key goes missing and you can't account for it, rekeying invalidates it immediately. This is especially relevant if the lost key was on a ring with an ID, address, or garage remote attached, since that's the scenario that actually worries people the most.
A roommate or tenant moves out. Whether you're a landlord managing a rental property or sharing a house with roommates, a rekey after someone moves out ensures they can't let themselves back in later, intentionally or not.
End of a relationship or a falling-out. Rekeying is a quiet, low-drama way to make sure an ex, a former business partner, or anyone else who used to have access no longer does.
Buying a used home in the South Bay. Real estate transactions in San Jose often move fast, and previous owners may have given out more keys than you'd expect over the years. A rekey is standard practice right after closing.
In every one of these cases, the underlying question a locksmith will ask is simply: is the lock itself working well? If the deadbolt throws smoothly, the key turns without effort, and there's no visible damage, rekeying is generally the more efficient path.
Replacement means installing a new lock — sometimes the same brand and style, sometimes an upgrade — rather than just changing what's inside the existing one. It's the better option in a handful of scenarios:
The hardware is worn, loose, or damaged. Locks take a beating over the years from weather, slamming doors, and general use. If the deadbolt is hard to throw, the strike plate is chewed up, or the cylinder wobbles, rekeying that lock just puts new pins into a mechanism that's already failing. Replacement fixes the actual hardware problem.
A break-in attempt or forced entry occurred. If a lock has been drilled, pried, bumped, or otherwise physically compromised, the internal mechanism may no longer be trustworthy even with new pins. Replacement is usually the safer route after any attempted or actual break-in.
You want a security upgrade. Rekeying keeps whatever security grade your current lock has. If you want a higher-security deadbolt, anti-pick or anti-bump features, or reinforced strike plates, that requires new hardware.
You're switching to smart locks or keyless entry. Adding a smart deadbolt, keypad lock, or app-controlled entry system means installing new hardware from the ground up — this isn't something a rekey can accomplish.
Mismatched or outdated hardware across the property. If a home has a mix of different lock brands, ages, and key types collected over the years, replacement lets you standardize everything, which sets you up nicely for the keyed-alike option below.
Locks made obsolete by a missing manufacturer or discontinued parts. Occasionally a lock is old enough, or from a brand no longer supported, that a locksmith can't source replacement pins. In that case, swapping the lock is the only real option.
A locksmith can usually tell within a few minutes of looking at your doors whether rekeying will hold up or whether replacement is the more honest recommendation. If a company just tells you to replace everything without checking the current hardware, that's worth a second opinion.
One of the most requested services alongside rekeying is "keyed-alike," where every exterior lock on a property — front door, back door, side entry, sometimes a gate or shed — is set up to open with the same single key. This is different from "keyed-different," where each lock has its own unique key.
Keyed-alike is popular for a simple reason: most people don't want to carry four different keys to get into their own house. It's especially common:
The tradeoff is worth knowing: keyed-alike means one lost key affects every door on the property, not just one. For most households the convenience outweighs that risk, but it's a fair thing to weigh, especially for a property with a detached garage, workshop, or rental unit where you might actually want separate keys on purpose.
Keyed-alike can be done during a rekey or a full replacement — it's a configuration choice, not a separate service, so it's worth mentioning it up front whichever route you choose.
Pricing for locksmith work varies by job, lock brand, number of doors, and time of day, so treat any numbers here as general ballpark ranges rather than a quote. A locksmith serving your specific San Jose or South Bay address can give you an actual price once they know the hardware involved and how many locks are on the property.
Rekeying is generally the less expensive of the two options per lock, since it reuses existing hardware and mostly involves labor and small parts (pins and springs). Pricing is typically quoted per lock, with a modest discount often available when rekeying multiple locks on the same visit — for example, rekeying an entire home's exterior doors in one appointment tends to cost less per lock than having someone rekey a single door on its own.
Replacement costs more because it includes the price of new hardware on top of labor. A basic knob-and-deadbolt combo sits at the lower end of the replacement range, while higher-security deadbolts, smart locks, or commercial-grade hardware push costs upward. If you're replacing several locks at once and want them keyed alike, that's usually more cost-effective than replacing them one at a time over several separate visits.
A few cost factors that tend to move the number either direction:
The only way to get a real number is a quick phone conversation where you describe the locks, the number of doors, and what you're trying to accomplish. Most locksmiths can give a reasonable estimate over the phone before ever showing up.
Rekeying is generally the quicker of the two jobs. A single lock typically takes well under an hour once a locksmith is on site and has the right pins for that lock model, and multiple locks on the same property can usually be done in one visit without a lengthy delay between them.
Replacement takes a bit longer per lock, since it involves removing the old hardware entirely, potentially adjusting the door prep if the new lock's dimensions differ slightly, installing the new unit, and testing that it operates smoothly. A single replacement is still normally a same-visit job; a whole-house replacement with several doors naturally takes longer than a whole-house rekey would.
Neither timeline should be treated as a guarantee — actual time on site depends on the condition of the door, the specific hardware involved, and whether anything unexpected turns up (a stripped screw, a warped door frame, a lock that's rusted in place). The best way to get a realistic sense of timing for your situation is to describe the job over the phone before scheduling.
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Is rekeying as secure as replacing the whole lock?
Rekeying makes old keys unusable, which addresses the most common security worry — that someone else out there still has a key. It doesn't change the underlying security grade of the lock itself, so if your current hardware is basic or worn, replacement is worth considering instead. For most everyday situations like a move-in or a lost key, rekeying provides the security improvement people are actually looking for.
Can I rekey a lock myself?
Rekeying requires disassembling the lock cylinder, correctly reading and cutting new pins, and reassembling everything so it still functions smoothly — it's a precision job, not a simple DIY swap. Doing it incorrectly can leave a lock that jams, doesn't fully lock, or gets damaged. Most people call a locksmith rather than risk damaging hardware they'd then need to replace anyway.
Do I need to rekey every door, or just the front door?
It's worth rekeying every exterior door, not just the one you use most. Previous keyholders may have had access to a back door, side entry, or garage just as easily as the front door, so leaving one lock untouched defeats some of the purpose. Many people choose keyed-alike at the same time so every rekeyed door still uses a single key.
How do I know if my lock is a good candidate for rekeying versus replacement?
The main thing to check is whether the lock currently operates smoothly — key turns easily, deadbolt throws without force, no looseness or visible damage. If it works well, rekeying is usually appropriate. If it's stiff, worn, damaged, or from an era where parts are hard to find, replacement tends to be the more practical route, and a locksmith can confirm this quickly in person.
What does "keyed-alike" actually mean, and is it right for my house?
Keyed-alike means multiple locks on your property are set up to open with the exact same key, so you're not juggling separate keys for the front door, back door, and side gate. It's convenient for most single-family homes, though it does mean one lost key affects every door it opens. If you have a detached unit like a garage apartment or rental you'd rather keep separate, you can request that one stay on its own key.
Should I rekey or replace locks after moving into a home in San Jose?
Rekeying is the typical recommendation right after a move-in, since it's usually enough to make sure old keys no longer work, and it's generally quicker and less costly than full replacement. The exception is if the existing locks are worn, damaged, or outdated enough that a locksmith recommends fresh hardware instead. Either way, doing this soon after moving in is a reasonable step for peace of mind.
How much does it cost to rekey a house full of locks?
Costs vary by job, depending on how many locks are involved, the brand and type of hardware, and whether it's done in a single visit. Rekeying multiple locks together in one appointment is generally more economical per lock than scheduling separate visits over time. A locksmith can give you a realistic estimate once they know how many doors and what type of locks you have.
Can a locksmith rekey locks from different manufacturers to use one key?
In many cases, yes — a locksmith can rekey compatible cylinders from different brands to share a single key, though this depends on the specific lock models involved. Some older or specialty locks may not be compatible with standard rekeying pin kits. It's worth mentioning all the lock brands on your property when you call so this can be checked ahead of time.
Last updated: August 2026
