Rekeying vs. Changing Locks: Which Do You Need?

Inside every pin-tumbler lock — the kind on virtually every residential door and most commercial doors — there are a series of spring-loaded pins that align only when the correct key is inserted. Rekeying means a locksmith disassembles the lock cylinder, swaps out those internal pins for a new set, and reconfigures them to match a brand-new key. Your existing lock hardware stays exactly where it is on the door. When the job is done, every old key that ever worked on that lock is now useless.

The whole process typically takes 10 to 20 minutes per lock for an experienced technician. Because no new hardware is purchased or installed, the cost is driven almost entirely by labor and the locksmith's service call. It's the reason rekeying is almost always the more affordable option — you're paying for skill and time, not materials.

Replacing a lock means removing the existing deadbolt, knob lock, or handle set entirely and installing completely new hardware in its place. The locksmith takes out the old lock body, strike plate, and sometimes the door prep work itself, and fits a new assembly. You end up with new hardware, a new key, and — if you choose a higher-grade product — potentially a stronger, more pick-resistant or bump-resistant lock than what was there before.

Lock replacement makes sense when the physical hardware is the problem, not just who has a copy of the key. It's also the right move when you want to upgrade your security grade, change lock brands so multiple doors can be keyed alike on one key, or when a lock has been physically damaged. The cost factors include the price of the hardware itself (lock grade, brand, and features like smart-lock capability all affect this), labor, and any door modifications needed.

Choose rekeying when: you've just moved into a home or apartment and the locks themselves are in good shape; a tenant, ex-partner, contractor, dog-walker, or anyone else had a key and you no longer want them to have access; you've lost a key and aren't sure where it ended up; or you want all the locks in your home to work on a single master key. In every one of these situations, the lock hardware is not the problem — the distributed key is. Rekeying solves it cleanly and quickly. If your locks are Schlage Grade 1 or ANSI-certified hardware in solid condition, there is genuinely no security advantage to replacing them just because a key got out.

Choose lock replacement when: the lock is visibly damaged, corroded, or stiff and difficult to operate; you've experienced a break-in attempt and the lock body itself has been stressed or compromised; the lock is an older, low-security model with no pick or bump resistance; you want to add smart-lock or keypad functionality; or the door prep doesn't align properly and is causing the lock to fail. In the Five Towns and Rockaways area, older homes often have builder-grade locks installed decades ago — these are worth replacing regardless of the key situation, because the hardware itself is the weak point.

Before you call a locksmith, spend two minutes at your door. First, look at the lock grade: Grade 1 is the strongest residential standard, Grade 2 is mid-range, Grade 3 is builder-basic. Many locks have the grade stamped inside the bolt housing or listed on the box if you still have it. Second, test the deadbolt — it should throw a full inch of bolt into the strike plate with no wobble. Third, look at the strike plate itself: a single-screw, thin-metal strike plate is a bigger vulnerability than the lock, and upgrading to a reinforced box strike with 3-inch screws is a $10–$15 hardware fix that dramatically increases kick-in resistance. If the lock passes these checks, rekeying is almost certainly all you need. If it fails any of them, it's worth discussing a full replacement with your locksmith.

Car owners: this same logic applies to automotive locks and transponder keys. If you're worried about who has a copy of your valet key or a spare you gave out, rekeying or reprogramming may resolve it without needing a full ignition replacement. A mobile locksmith who handles automotive work — like our team serving the JFK area and surrounding communities — can walk you through the options on-site.

For rekeying, the main cost factors are: the number of locks being rekeyed (doing multiple locks in one visit is more efficient and usually more economical), the lock brand (some require proprietary tools or pins), and whether it's a standard service call or an after-hours emergency. For lock replacement, costs are shaped by the grade and brand of the new hardware you choose, whether the door needs any modification to accept the new lock, the number of locks being replaced, and labor time. Smart locks and high-security cylinders (Medeco, Mul-T-Lock, etc.) carry higher hardware costs but offer meaningful upgrades in pick, bump, and drill resistance.

One practical tip: if you're rekeying multiple locks in a home, ask your locksmith to key them alike — meaning all doors operate on one key. This is done during the rekeying process at minimal added cost and eliminates the everyday frustration of carrying multiple keys. It's one of those small upgrades that makes a real quality-of-life difference.