Rekey or Replace? How to Decide (and What Each Costs)

What rekeying actually does

Inside every pin-tumbler lock is a row of small pins that must line up exactly with the cuts on your key. Rekeying swaps those pins for a different set, so a new key lines them up and the old key no longer does. The lock body, the deadbolt, the knob, the finish: all unchanged. It takes about ten minutes per lock and, because nothing is replaced, it's the cheapest way to make every existing key useless.

What replacing does

Replacement swaps the whole lock: cylinder, bolt, housing and trim. You get new hardware, which matters when the old lock is physically worn, when it's corroded from salt air, when it's a low-grade builder lock, or when you want features the old lock doesn't have, like a Grade 1 rating, a high-security cylinder or a keypad. It costs more because you're buying hardware plus labor, and it's the only option when the lock itself is the problem.

Rekey if…

• You just bought a home or moved into a rental and the locks are in good shape.
• A key was lost or stolen, or someone who had a key shouldn't anymore.
• You want one key for every door instead of a ring full of them.
• You've handed out so many copies you've lost count.
• The locks are decent brands with no rust, no wobble and a key that turns cleanly.

Replace if…

• The key sticks or barely turns and cleaning didn't fix it. Near the beach this is usually salt corrosion inside the cylinder.
• The lock is loose, the bolt doesn't throw fully, or the knob spins.
• The door has a keyed knob and no deadbolt. That isn't a rekey problem; it's a missing-lock problem.
• You want a real upgrade: Grade 1 hardware, a restricted keyway, a smart lock.
• After a break-in, even if the lock still works. See our after a break-in guide.

The San Diego version

Where you live changes the answer. Cottages in Ocean Beach and Mission Beach often have hardware too pitted to be worth rekeying, and a coastal-rated replacement is the smarter spend. The same lock on a house in Clairemont or Mira Mesa is usually fine to rekey. Craftsman bungalows in North Park often have original mortise locks that can be rekeyed and kept, with a modern deadbolt added beside them. Newer homes in Carmel Valley mostly need rekeys, with builder-grade handlesets replaced as they wear out around year ten.

Can you do both?

Often the right answer is a mix: replace the worn front deadbolt, rekey the three good locks on the other doors, and key all of it to one new key. A locksmith who looks at each door instead of quoting one answer for the whole house will save you money. Ask on the phone and expect an honest split.

Written by Mark Hanna, owner and lead locksmith of Action Locksmith San Diego (CA LCO License #7199). Published 2026-09-04, last updated September 4, 2026. Prices mentioned are typical San Diego ranges; see the prices page for details.