Rekey or replace your locks? How to decide.

What does rekeying a lock actually do?

Most door locks use a pin tumbler cylinder: a row of small spring-loaded pins that line up only when the right key is inserted. Rekeying means a locksmith takes the cylinder apart and replaces those pins with a new set that matches a new key.

The result: the lock, handle, and deadbolt stay exactly where they are, but every old key stops working. Nothing on the door changes except which key opens it.

When is rekeying the right call?

Rekeying is the right choice when the hardware is in good shape and the problem is who has keys:

• You just moved in. You have no way of knowing how many copies of the old keys exist.
• Keys were lost or stolen, especially if they were with anything showing your address.
• A roommate, tenant, employee, or contractor had keys and no longer should.
• You want one key for every door. Locks can be rekeyed to a single key as long as they share the same keyway. A Schlage and a Kwikset lock, for example, take different key blanks, so matching them usually means replacing one cylinder.

When should a lock be replaced instead?

Replace the lock when rekeying would be putting new pins in hardware that no longer does its job:

• It was forced or damaged. A bent bolt, cracked housing, or damaged strike after a break-in should be replaced, not rekeyed.
• It is worn out. Keys that stick, a bolt that drags, or a knob that wobbles are signs the mechanism itself is failing.
• You want more security. Deadbolts are rated by ANSI/BHMA grade, with Grade 1 the strongest. High-security cylinders from brands like Medeco or Mul-T-Lock add pick and bump resistance and key control, meaning copies cannot be cut at a hardware store.
• You want keyless entry. A keypad or smart lock replaces the existing hardware.
• Mismatched brands. If you want one key for the whole house and the locks use different keyways, replacing the odd ones out is often simpler.

How is this different for a business?

The same logic applies, at a larger scale. Tenant turnover and staff changes are the most common reasons to rekey commercial locks. Buildings with a master key system can often rekey only the affected cylinders after a lost master key, rather than replacing the whole system.

Buildings that change occupants often may benefit from interchangeable-core cylinders, where a locksmith swaps the core in seconds instead of rekeying on site. Access control goes a step further and replaces keys with cards, fobs, or codes you can revoke instantly. See the access control guide.

What should you ask a locksmith first?

• Are you licensed in Maryland? Maryland requires locksmiths to be licensed. Ask for the number and check it on the Maryland Department of Labor license lookup. Lock Raven's license is #737.
• What will it cost, before you start? A reputable locksmith prices the job before any work begins.
• Should I rekey or replace? An honest answer depends on the condition of the lock. If rekeying is enough, you should hear that.