Rekey or replace — which one you actually need

Rekeying keeps your existing locks on the door and changes the pins inside, so old keys stop working and a new set takes over. Replacing swaps the hardware entirely. They get sold interchangeably, but they answer different questions: rekeying answers "who can get in?", replacement answers "is this lock still any good?"

If the hardware is sound and the only thing that changed is people — a move, a breakup, a lost key ring, a contractor who had a copy — rekeying the existing locks does everything replacement would, for less, in less time. Paying for new hardware in that situation buys you nothing but new hardware.

A lock that has mechanically worn out cannot be rekeyed into health. The tells: a key that needs jiggling ritual to turn, a bolt that grinds instead of throwing, a cylinder that spins loose in its housing, visible corrosion on an exposed door. Rekeying a dying lock transfers new keys onto a mechanism that is still dying.

Replacement is also the answer when you want the lock to do something different — a deadbolt where there is only a knob latch, a thumbturn inside instead of a double cylinder, a keypad instead of a key. And on Lawrence's older doors, some antique mortise hardware has simply reached the end of parts availability; swapping the lockset is the only move left.

Real houses usually land in between: a front door lock worth keeping, a back door lock that should have been retired years ago, and a side door nobody has locked since the Clinton administration. The right visit rekeys the good hardware, replaces the failed piece, and keys everything alike so one key runs the house.

That last part is worth insisting on. Keyed-alike costs almost nothing when the work is already happening and is annoying to retrofit later. It is also the moment to fix the thing that usually caused the trouble — a strike plate a few millimeters out of line from a door that has settled, which makes a healthy lock feel broken and gets a lot of hardware replaced for no reason.

Ask three questions. Does the key turn smoothly when the door is open? If yes, the cylinder is probably fine and your problem is alignment, not the lock. Did the set of people holding keys change? If yes, rekey regardless of what else you do. Do you want the door to behave differently — more security, no key at all, one key for everything? If yes, that specific door is a replacement.

Anyone who quotes full replacement across the whole house without asking those questions is selling hardware, not solving your problem. The broader picture of what a house needs over its life is on our residential locksmith page — this decision is the one that comes up most.