The core difference: rekeying changes who can enter, replacement changes everything
Rekeying adjusts the internal pin configuration of an existing cylinder so that old keys no longer work and a new key is cut to match. The hardware — the bolt, the housing, the strike plate — stays in place. Lock replacement removes the entire lockset and installs new hardware from scratch. Both operations achieve the same immediate goal of access control reset, but they differ significantly in cost, time, and what they address beyond the key itself.
A rekey typically takes a locksmith ten to twenty minutes per cylinder and costs a fraction of replacement. Replacement involves hardware cost plus labor and takes thirty to sixty minutes per door depending on the existing prep and the new hardware spec. The decision framework is not complicated, but it requires an honest assessment of the existing lock's condition and your security goals.
When rekeying is clearly the right choice
Choose rekeying when the existing lock hardware is in good working condition and your goal is purely access control reset. The most common rekeying triggers: moving into a new home or rental unit, ending a relationship with someone who had key access, losing a key with no certainty that it was not found or copied, completing a renovation where contractors held keys, and transitioning property management.
If the lock is a Grade 1 or Grade 2 ANSI-rated cylinder, less than ten years old, operates smoothly, and does not have a history of forced tampering, rekeying is the cost-effective and sufficient response. There is no security benefit to replacing a functional high-quality lock when the only goal is key invalidation.
Rekeying is also the right tool for normalizing a property after extended multi-party key distribution. A rental unit that had five tenants over three years likely has an unknown number of key copies in circulation. A full rekey of all cylinders — front door, back door, common area locks — costs less than an evening's dinner and closes off all those legacy access paths simultaneously.
When lock replacement is the better investment
Replace the lock when the hardware itself is the problem, not just the key. Worn cylinders that require jiggling to operate, sluggish deadbolts that do not extend smoothly, mechanisms with a broken thumb-turn, and locks damaged from a prior break-in or attempted entry all warrant replacement rather than rekeying. Rekeying a cylinder that is mechanically compromised leaves you with a freshly keyed lock that still fails on a bad day.
Replace when upgrading security grade is the goal. If the existing deadbolt is Grade 3 or an off-brand cylinder with no ANSI rating, and you want Grade 1 protection, rekeying cannot solve that problem — it only changes the key. Upgrading to a Schlage, Kwikset, or ASSA ABLOY Grade 1 cylinder, or stepping up to a restricted-keyway high-security cylinder, requires physical replacement.
Also replace if the lock brand or cylinder cannot be rekeyed cost-effectively. Some older European-style cylinders, mortise locks with proprietary pins, or cheap builder-grade locksets have cylinders that are incompatible with standard rekey kits. A locksmith will identify this during assessment, and in those cases, replacement becomes the practical path regardless of the original intent.
The role of key control in this decision
Standard keyways — SC1, KW1, and similar common profiles — can be duplicated at any hardware store, key kiosk, or locksmith. If your concern is not just current key holders but future unauthorized duplication, a rekey into the same standard keyway does not solve the problem. Someone with a copy of the old key can still have a copy of the new key made at any retail kiosk.
If key control is a concern — contractors, ex-employees, or tenants who may have duplicated keys without authorization — the appropriate upgrade is a restricted-keyway cylinder. Medeco, Mul-T-Lock, and ASSA ABLOY High Security cylinders use patented keyways that cannot be duplicated without authorization from the registered dealer. This requires lock replacement, not just rekeying, but it permanently addresses the duplication vulnerability for the life of the hardware.
Cost comparison: what to budget
Rekeying in the DC metro area typically runs $25 to $50 per cylinder for a scheduled visit, with multi-cylinder discounts common for whole-property rekeys. A full home with three exterior cylinders and two interior locks can often be rekeyed in under an hour. Emergency or same-day rekeying carries a premium.
Lock replacement costs include both hardware and labor. A quality Grade 1 deadbolt runs $60 to $150; a high-security cylinder replacement can run $200 to $400 per door. Installation labor adds $50 to $100 per door for standard residential work. For a home with multiple exterior doors requiring security upgrades, budget accordingly and prioritize by entry point — front door and attached entry doors first.
Related services
- Lock rekeying service: /services/lock-rekeying
- Deadbolt installation and upgrade: /services/deadbolt-installation
- High-security lock upgrade: /services/high-security-locks
- Residential security assessment: /services/residential-locksmith
Frequently asked questions
How many times can a lock be rekeyed before it needs replacement?
Most quality cylinders can be rekeyed multiple times without degradation. The limiting factor is the condition of the cylinder pins and springs, not the number of rekeys. A cylinder that has been rekeyed five times but operated gently may be in better condition than one rekeyed once that has been subjected to heavy use or forced entry. Annual inspection is more informative than counting rekey events.
Can I rekey my own locks with a DIY kit?
DIY rekey kits are available for common brands like Schlage and Kwikset. They work adequately if you follow the instructions carefully. The risk is pin sequence error — loading the wrong pin depth creates a cylinder that may work intermittently or bind under temperature-related door frame movement. Professional rekeying costs little and eliminates that risk, particularly for exterior doors where failure means a lockout rather than a merely inconvenient interior door.