Rekey vs. Replace: What's the Actual Difference?
People use these words as if they mean the same thing. They don't, and the difference is exactly what determines your cost.
Rekeying means a locksmith opens up the lock cylinder you already own and swaps the small internal pins for a different combination. Your old keys no longer fit; you get a fresh set that does. The lock on your door — the knob, the deadbolt, the finish — stays exactly the same. Only the "code" inside changes.
Replacing means removing the entire lock and installing brand-new hardware. You'd do this when the physical lock itself needs to change — because it's broken, worn, outdated, or you're upgrading to something better like a smart lock.
The simplest way to think about it: Rekeying changes who can open the lock. Replacing changes the lock itself. If your hardware is fine and you just need old keys to stop working, you're describing a rekey.
Cost Comparison (Arizona, 2026)
These are realistic Arizona rates. The gap is the whole point — rekeying reuses hardware you already paid for, so you're only paying for labor and new pins.
| Option | Typical Cost | What You Get |
|---|---|---|
| Rekey — first door | $149 TrustKey flat rate |
New pins + 2 keys cut on-site, ~20 min |
| Rekey — each add'l door | +$49 | All doors on one matching key |
| 3-door home rekey | $247 | Front, back, garage entry — one key |
| Replace — standard deadbolt | from $249 | New Schlage B60N installed, all-in |
| Replace — smart lock | from $369 | Schlage Encode, hardware + install |
| Install labor only (your lock) | from $149 | You supply the hardware |
Rough rule of thumb: rekeying costs about half of replacing for the same door, and gives you identical security. The extra money in a replacement pays for new hardware, not better locks — so only spend it when you actually want new hardware.
When Rekeying Is the Right Call
Rekey when the lock works fine and your real goal is to control who has a working key. That covers most situations:
- You just moved into a home — the single most common reason (more on this below)
- You lost a key — if a key is missing and you don't know where it is, rekeying makes it useless
- A roommate, tenant, or ex moved out — and you're not certain every copy came back
- You've handed out too many copies — contractors, dog walkers, cleaners, the neighbor who watered your plants three summers ago
- You want all doors on one key — a locksmith can rekey mismatched locks (as long as they share a keyway) so a single key opens everything
When You Should Replace Instead
Replacing is worth the extra cost when the hardware itself is the problem — or when you want it to do more than it currently does.
✅ Replace when…
- The lock is damaged, sticking, or the key turns roughly
- It's old and worn — decades of Arizona sun and dust take a toll
- You want to upgrade to a smart lock or keypad
- You want a higher security grade (ANSI Grade 1/2 deadbolt)
- The finish or style no longer matches a renovated door
- Doors use different keyways and can't be rekeyed to one key
↩ Rekey is enough when…
- The lock turns smoothly and looks fine
- You just need old keys to stop working
- You want to save roughly half the cost
- You want existing doors matched to one key
- It's a fresh move-in with working hardware
Moving Into a New Arizona Home? Do This First
This is the situation where the choice matters most. When you get the keys to a new place, you have no idea how many working copies exist. The previous owner, their kids, the real-estate agent, the lockbox, cleaners, landscapers, contractors — any of them could still have one. The house is only as secure as the number of keys you can't account for.
A move-in checklist that actually closes that gap:
- Rekey every exterior door the week you move in — front, back, side, and the garage-to-house entry door
- Put them all on one key while you're at it — no reason to juggle three keys for your own house
- Check the garage door opener codes and reset them; old remotes may still work
- Replace, don't rekey, anything already damaged — a move-in is the natural time to upgrade a tired lock or add a smart deadbolt
Why rekey rather than replace on move-in: unless a lock is damaged, the hardware a builder or previous owner installed is usually fine. Rekeying every door invalidates every unknown copy for roughly half the price of new hardware — the security outcome is the same.
Can You Rekey a Lock Yourself?
Sometimes. It depends on the lock:
- Kwikset SmartKey and similar consumer locks can be rekeyed at home in minutes with a small tool — if you still have a working key. This is genuinely DIY-friendly for one or two locks.
- Standard pin-tumbler locks (most deadbolts and knobs) need a brand-specific rekey kit, a plug follower, and a steady hand. It's doable, but the first attempt usually takes a while and it's easy to lose the tiny pins and springs.
- Matching several doors to one key is where DIY gets hard — getting multiple cylinders to accept the same new key reliably is fiddly. This is the main reason people call a pro even when they own the tools.
If you have one Kwikset SmartKey deadbolt and a working key, buy the kit and try it. If you have a whole house of mixed hardware and want one key for all of it, a locksmith will do the entire home in under an hour with everything matched.
Frequently Asked Questions
Is it cheaper to rekey or replace a lock?
Rekeying is almost always cheaper. In Arizona it runs about $149 for the first door and +$49 for each additional door, versus $249+ per door to replace with new hardware. Rekeying reuses your existing lock and only changes the pins inside.
Does rekeying make old keys stop working?
Yes — that's the entire purpose. After a rekey, every previously working key is permanently useless, and you get a new set. It's the reliable way to lock out copies you can't track down.
Should I rekey or replace after moving into a new house in Arizona?
Rekey, for most move-ins. You can't know how many old keys are out there, and rekeying every exterior door invalidates all of them for far less than replacement. Replace only the locks that are already damaged, or when you want to upgrade to a smart lock.
Is rekeying as secure as replacing?
For the same lock, yes. Rekeying changes the combination inside the cylinder — an old key won't open it. Replacing only improves security if you're moving up to genuinely better hardware (a higher grade or a smart lock). Same-for-same, the security is identical.
How long does it take to rekey a house?
About 20 minutes per lock. A typical 3-door Arizona home is done in under an hour, including cutting new keys on-site and matching every door to a single key.