Rekeying vs Lock Replacement: Which Should You Choose?

When you move into a new house, change a roommate, lose a key, or have any other reason to want different keys on your doors, you have two basic options: rekey the existing locks, or replace them with new ones. Most homeowners default to "replace" because that is what feels permanent — but in many situations, rekeying is the smarter call by every measure.

Here is the honest decision tree we walk Jacksonville homeowners through.

What "rekey" actually means

A residential deadbolt has a cylindrical body with several spring-loaded pins inside. When you insert the right key, the cuts on the key push each pin to exactly the right height, and the cylinder rotates freely. When you insert the wrong key, at least one pin sits at the wrong height, blocking rotation.

Rekeying means changing the heights of those pins so that a different key (and only that key) opens the lock. The mechanical lock body, the strike plate, the screws, and everything else stays in place. Only the small pins inside the cylinder are swapped.

The process for one lock takes about 5–10 minutes once the cylinder is removed. A typical 4-lock house takes 45–75 minutes start to finish.

What "replace" means

Full replacement means removing the entire lock — cylinder, body, strike plate, sometimes the screws — and installing a new lock in its place. The new lock comes with its own keys.

The process for one lock takes 15–30 minutes for a straightforward replacement, longer if the door prep needs adjustment.

The cost comparison

For a typical Jacksonville home with 4 exterior locks (front door, back door, garage entry, side door):

So the cost difference is significant — rekeying is typically 60–80% cheaper than replacing.

When rekeying is the right answer

Rekey instead of replacing when:

You just moved in

This is the textbook rekey scenario. The locks are usually fine — they were installed when the house was built or last renovated, and they work. You just need to make sure no one but you has a working key.

You have no way to know how many copies of the previous owner's keys exist:

• Family members of the previous owner
• Their ex-partners
• Real estate agents (often have lockboxes with copies)
• Contractors who worked on the house
• Cleaners, dog walkers, neighbors
• Previous tenants if it was a rental

Rekeying makes every existing copy of those keys non-functional in 60 minutes.

You changed a roommate or family member moved out

Same logic. Rekey, distribute the new keys to current residents only, done.

You lost a key and don't know where it is

If the lost key is not labeled (no tag with your address), the practical risk is very low. But if you have any concern — or if the key was on a labeled keychain — rekey the affected locks.

You want all your exterior doors keyed alike

If you have separate keys for the front door, back door, and garage entry, rekeying all of them to a single matched key is a common and inexpensive request. Eliminates carrying multiple keys.

Your locks are working fine but you just want fresh keys

Your existing locks are mechanically sound; you just need different keys. Rekey.

When full replacement is the right answer

Replace instead of rekeying when:

The locks are mechanically failing

If the cylinders are sticking, the deadbolts are rough to throw, the latches are not retracting smoothly, or any other mechanical issue is happening, the locks are at the end of their life. Replace them.

The locks are low builder-grade quality

Many newly-built homes ship with the cheapest Grade 3 locks the builder could find. These are pickable in seconds by anyone with basic skills, have weak strike plates, and start failing within 5–10 years. If you are doing a security upgrade anyway, replace with Grade 1 quality locks rather than rekey low-quality ones.

You are upgrading to electronic or smart locks

If you want to add a keypad or smart lock to your front door, you have to replace the existing lock — there is no rekey-to-electronic option.

The lock has been damaged in a break-in attempt

Forced entry damages the strike, the latch, sometimes the cylinder. Even if it still works, the structural integrity is compromised. Replace.

The lock is corroded from Florida humidity

Locks installed on exposed exterior doors (no overhang, direct rain or sun) deteriorate faster in Florida than other parts of the country. After 8–10 years of exposure, the internal pins may be rusty enough that rekeying is unreliable. Replace with marine-grade hardware.

You want a different lock style

If you are switching from a single-cylinder to a double-cylinder, or want a different visible finish, replacement is necessary.

A hybrid approach: rekey some, replace others

The most common real-world situation is a mix. For example:

• Front door: replace with a quality Grade 1 lock or keypad lock (this is the door visible from the street and the most-used entry)
• Back door / patio: rekey the existing builder-grade lock to match the new front door key
• Garage entry door: rekey, key alike with the front
• Side gate: rekey or replace depending on condition

This kind of hybrid plan often saves $300–600 vs full replacement while still upgrading the most important door and getting all keys matched.

What about smart locks?

Smart locks deserve their own answer. If your existing locks are mechanically fine and you do not specifically need keypad or app features, rekeying is far cheaper than upgrading to smart locks. If you do want smart features (kids losing keys, frequent guests, short-term rental), replacement is required and worth the cost.

We covered the full smart lock vs deadbolt tradeoff in our Florida home security guide.

Common rekey mistakes to avoid

A few things that go wrong when people try to handle this themselves or use the wrong service:

• Buying a "rekey kit" online for a lock brand they don't actually have. Rekey kits are brand-specific. The wrong kit means a wasted $30 and a lot of frustration.
• Trying to rekey high-security locks (Medeco, Mul-T-Lock, ASSA, Abloy) without the manufacturer's restricted keyway access. These need a locksmith with the right credentials.
• Forgetting an exterior door. Side doors, garage entry doors, and pool gates are easy to overlook. Rekey everything that should accept the new key.
• Not testing each lock with the new key after rekeying. Always test from both sides of the door (especially for double-cylinder locks).

What the appointment looks like

A typical rekey appointment in Jacksonville:

1. Quote on the phone — number of locks, type, condition. Quote is good for 24 hours.
2. Arrival — usually within 1–2 hours of scheduling for non-emergency appointments.
3. Inspection — quickly check each lock to confirm they are good candidates for rekeying (vs needing replacement).
4. Rekey — 5–10 minutes per cylinder, working through the doors one at a time.
5. New keys cut — typically 3 keys per matched system, more available for $3–5 each.
6. Test all locks — work through each door from inside and outside, confirm everything operates smoothly.

Total visit time: 60–90 minutes for a typical 4-lock house.

What Koala Locksmith offers in Jacksonville

We rekey, replace, and upgrade locks across the Jacksonville metro for homes, condos, and rentals. Whether you just bought a house, changed a roommate, lost a key, or want to upgrade to a smart lock, we can give you a flat phone quote with no surprises on arrival.

For a fast quote, call +1 (904) 515-9573 with the number of doors you need rekeyed. For non-urgent jobs you can request a quote here. We cover all of Jacksonville, the beaches, San Marco, Mandarin, Arlington, Northside, and Orange Park.