Rekeying vs Replacing Locks: Which Do You Actually Need?

When you need new locks, the first question is rarely the right one. Most people ask "how much does it cost to replace my locks?" when the question they should be asking is "should I rekey or replace?" The answer affects cost, security, and how long the work takes.

This article walks through the difference, when each option makes sense, and what to ask a locksmith before agreeing to a service.

What rekeying actually means

Rekeying changes the internal pins of an existing lock so that an old key no longer works and a new key is needed. The lock itself stays in place — the doorknob, deadbolt, and visible hardware are unchanged. Only the small pins inside the cylinder get swapped.

Rekeying is fast. A locksmith can typically rekey a standard residential lock in five to ten minutes. The work uses inexpensive pin kits that cost very little compared to a new lockset. As a result, rekeying costs significantly less than replacement — usually twenty to fifty dollars per lock for the rekeying itself, plus a service call fee.

What replacing locks involves

Replacing a lock means removing the existing hardware and installing entirely new locks. The new lock comes with its own keys, internal pins, and physical hardware. Depending on the lock chosen, replacement can run from fifty dollars for a basic deadbolt to several hundred for a high-security lock or a smart lock with electronic features.

Replacement makes sense when the existing lock is old, damaged, or no longer meets your security needs. It is also the right answer when you want to upgrade — moving from a Grade 3 builder-installed lock to a Grade 1 high-security lock requires replacement, not rekeying.

When to rekey

The most common reason to rekey is moving into a previously owned home. The previous owners, real estate agents, contractors, cleaning services, and pet sitters may all have had keys at some point. Rekeying is the fastest, cheapest way to ensure you control who has access. The cost is low, the disruption is minimal, and the security benefit is immediate.

Rekeying is also the right call when a key has been lost or stolen, when an employee with key access leaves, when a relationship ends, or any other situation where the key may be in unwanted hands but the lock itself is still in good condition.

When to replace

Replacement is the right answer in several scenarios. If the lock is visibly worn, sticking, or not closing smoothly, the internal mechanism is approaching failure and rekeying only delays the inevitable. If the lock is from a low-grade builder-installed batch, replacement gives you the chance to upgrade to a more secure option.

Replacement is also necessary when there has been an attempted break-in. Even if the lock held, the internal mechanism may have been damaged or weakened in ways that aren't visible from outside. A locksmith inspecting the lock after a break-in attempt may recommend replacement specifically because the lock can no longer be trusted to perform reliably.

Finally, replacement is required when changing lock types — for example, moving from a standard deadbolt to a smart lock, or from a key-only lock to a key-and-keypad combination. These are physical hardware changes that rekeying cannot accomplish.

Mixing approaches

For many homes, the right answer is a mix. Replace the front door deadbolt with a higher-grade or smart lock as an upgrade. Rekey the side door, back door, and garage entry to keep the existing hardware but eliminate any old keys in circulation. This approach provides the security benefit of new locks where it matters most while controlling cost on doors that don't need hardware upgrades.

A locksmith doing a whole-home review can identify which approach makes sense per door rather than treating every door the same way.

Asking a locksmith for the right service

When you call a locksmith, describe the situation in plain terms. "I just bought a house and want to make sure the previous owner's keys don't work" leads to a rekeying recommendation. "My deadbolt is sticking and I can barely turn the key" leads to a replacement recommendation. Don't ask only "how much for new locks" — let the locksmith tell you what the situation actually calls for.

A reputable locksmith will not push replacement when rekeying would do the job. If you ever feel pressured to spend more than the situation requires, that's a sign to get a second opinion.

Cost comparison summary

For a home with three exterior doors, rekeying typically costs one hundred to two hundred dollars total including a service call. Full replacement with mid-grade locks runs three to six hundred dollars. High-security or smart lock replacement can reach eight hundred dollars or more. The right choice depends on what the locks look like now and what your security needs are — not just price.

Maintaining the new keys

Whichever approach you choose, the new keys are only useful if you maintain control of them. Make a few copies for trusted family members, but resist the urge to make extra copies "just in case." Each additional key is a security risk if it goes missing. A spare with a trusted neighbor, a small lockbox on the property with a combination only you know, or a smart lock keypad code for backup access are all better than copies in unknown hands.

When to do it again

Rekeying or replacing once isn't the end of the security cycle. Anytime a key goes into uncertain circumstances — lost, stolen, given to someone whose role changes, used by a service provider you no longer use — the question of whether to rekey again comes back. The cost is modest each time, and the security benefit accumulates over years of careful key control.