Lost Your House Keys? Rekey or Replace — An Honest 2026 Guide

Losing house keys is stressful — partly because the keys themselves are easy to replace, but the question of who else might have them isn't. Here's the working-locksmith's guide to deciding between rekeying (keeping your existing locks, changing what key opens them) and replacing the locks entirely.

First — has the keyring been stolen or just misplaced? If you've genuinely just dropped the keys somewhere (lost in a coat pocket, left at a friend's, slipped down between sofa cushions), the security risk is low. If the keys have been stolen — particularly along with anything identifying your address (driving licence, post, fob with house number) — assume the worst and change the locks.

What rekeying actually means. On mortice locks (5-lever BS3621), rekeying isn't really a thing — the locks are usually replaced. On euro cylinders (UPVC, composite doors), 'rekeying' means swapping just the cylinder (the bit the key goes into) while keeping the handles, mechanism and door hardware. Practically, it's a cylinder change — the same job whether the old keys are lost or you're upgrading for security.

Cost comparison.

When rekeying is sufficient. If only the keys are lost (no wallet, no address details), the risk that anyone can match the keys to your specific door is low. A cylinder change brings the security back to 'baseline' for relatively little cost. This is the typical recommendation after a routine key loss with no theft involved.

When full replacement is the right call. After a burglary (the burglar may have taken keys deliberately). After a stolen handbag or wallet that included keys and address ID. After a separation, divorce or housemate move-out where you can't guarantee return of all copies. After buying a property where you can't be sure how many copies the previous owner cut. End-of-tenancy for landlords (almost always full cylinder change between tenants).

Should you upgrade while you're at it? If you're already paying for a cylinder change, this is the moment to consider upgrading to TS007 3-star anti-snap.

Keyed-alike: a small extra spend, large convenience win. If you have multiple external doors (front, back, French doors, side door) all with euro cylinders, you can have them supplied keyed alike — one key opens all four.

Smart locks as an alternative. Smart locks (Yale Conexis, Ultion Nuki, August Wi-Fi) eliminate physical keys — you unlock by phone, code or fob. Worth it if you regularly lose keys, if multiple family members need access, or if you let the property short-term. Less worth it if you just want a one-time fix.

The honest summary. Either way, a 30-minute visit from a working locksmith resolves the problem, restores security and provides a written 12-month guarantee.