Rekey vs. Replace: Which Do You Need?

Rekeying changes who can open your existing lock; replacing installs new hardware. Here's how to choose — and save money doing it.

By Jared Dygert · Licensed Locksmith, CA #LOC8542

When you need to change who can get into your home, you have two options: rekey the locks you already have, or replace them with new hardware. Most people don't need to replace — here's how to tell which one is right for you.

What rekeying means

Rekeying changes the small pins inside your existing lock so that your old keys no longer work and a brand-new key does. The lock itself stays on your door — only the internal "code" changes. It's fast, affordable, and the lock keeps working exactly as before.

What replacing means

Replacing means removing the old hardware and installing a brand-new lock. You'd do this when the lock is worn out or damaged, when you want a different style or finish, or when you're upgrading to higher security or a smart lock.

When to rekey

  • You just moved in. You have no idea how many keys are floating around — rekey everything.
  • You lost a key or had one stolen.
  • After a roommate, tenant, or relationship change.
  • Too many copies are out there — contractors, dog walkers, former housekeepers.
  • You want every door on one key. A locksmith can usually rekey several locks to a single key, even mismatched brands.

When to replace

  • The lock is worn, sticky, or damaged and not operating smoothly.
  • You want to upgrade security — a higher-grade deadbolt or a bump/pick-resistant cylinder.
  • You're adding a smart or keypad lock.
  • The hardware is old or mismatched and you want a consistent look.
Rule of thumb: if the lock works fine and you only need to control who has a key, rekey. If the hardware is failing or you want an upgrade, replace.

Cost and time

Rekeying is almost always cheaper because there's no new hardware to buy and it takes just a few minutes per lock. Replacing costs more because you're paying for the new lock plus installation. If budget matters and your locks are in good shape, rekeying gets you the same security benefit — old keys stop working — for less.

Can you do it yourself?

Hardware-store rekey kits exist, but they only work within one brand, can be fiddly, and won't get multiple doors onto one key reliably. A licensed locksmith can rekey mixed brands, get everything on a single key, and confirm each lock is working correctly before leaving.

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