The quick answer

If your door is uPVC or composite — which most are — replacing the cylinder is usually the better deal. It costs about the same as rekeying and you end up with a new lock instead of a repinned old one.

If you've got a solid wooden door with a good British Standard mortice lock, rekeying that lock makes real sense. It's a decent bit of hardware and worth keeping.

Why most advice you'll read is wrong here

Search this question and you'll mostly find American articles, because rekeying is routine in the US and genuinely the cheap option there. That advice gets repeated on UK sites without anyone checking whether it still applies.

It largely doesn't. A euro cylinder — the barrel in a uPVC door — is designed to come out in about a minute: one screw on the edge of the door and it slides free. There's no meaningful labour saved by repinning it in place, so the price lands in much the same spot either way. Given the choice between a new cylinder and a repinned old one for similar money, the new one is the easy call.

It depends on why you're changing it

This is the part that actually decides it, and it gets skipped in favour of arguing about price:

Your situationWhat I'd do
Just moved inReplace — and upgrade while you're at it
Lost your keysEither; replace on uPVC
Ex-partner or old tenant has a keyEither — both stop the old key working
Break-in through a snapped cylinderReplace with 3-star. Not negotiable
Lock stiff, sticky or failingReplace — rekeying won't fix worn parts
Good mortice lock, just want new keysRekey

Notice how few of those are really about saving twenty quid.

Moving house: the one people underthink

When you move in, you have no idea how many keys exist. Not just the previous owner — their family, a cleaner, a builder, an old lodger, an estate agent's spare that never came back. Nobody is keeping a register.

So changing the locks is sensible. What's worth realising is that if you're paying for that anyway, the marginal cost of moving up to a TS007 3-star anti-snap cylinder at the same time is small. Rekeying gets you new keys and leaves you with whatever grade of lock the last owner happened to buy.

"Had keyed alike barrels fitted for my patio doors — arrived on time, explained everything clearly, completed quickly. Stress free from start to finish."

Liaa T, Nottingham

Keyed alike: ask for it while someone's there

If you're changing more than one lock, they can be set up to take the same key — front, back, garage, patio. It's called keyed alike, and people consistently don't ask for it because they don't know it's an option.

Doing every door in a single visit costs less than calling someone out three times, and you stop carrying a keyring that looks like a caretaker's.

What it costs

A lock change is £70–£90 fitted on my price list, fixed and quoted before I start — the spread is the part, not the labour. Rekeying is something I'll do where it's genuinely the better answer, and I'll tell you when it is rather than defaulting to whichever pays more.

If a locksmith pushes rekeying hard on a uPVC door without explaining why, or insists on full replacement of a perfectly good mortice lock, ask them to justify it. A straight answer is easy for anyone who isn't working an angle.

Not sure which you've got?

Send me a photo of the edge of your door. If it's a euro cylinder you'll see a barrel; if it's a mortice you'll see a rectangular plate. I'll tell you which applies and what it'd cost, with no callout for the question.

Call or text 07414 727717 — across Beeston, Bulwell, Arnold, West Bridgford, Hucknall, Ilkeston and Derby.

FAQ

What's the difference between rekeying and replacing?
Rekeying changes the pins inside the lock you already have, so old keys stop working and you get new ones. Replacing swaps the lock itself for a new one. Rekeying keeps the existing hardware; replacing gives you a different lock, which matters if the old one wasn't up to much.
Is rekeying cheaper in the UK?
Not usually, and this surprises people. Most rekeying advice online is American, where it's routine. On a UK uPVC or composite door the euro cylinder simply pulls out and a new one goes in, so replacing costs about the same as rekeying — and you end up with a new lock rather than a repinned old one.
When is rekeying the better option?
On a good wooden door with a quality British Standard mortice lock that's in sound condition. That lock is worth keeping, and repinning it is cheaper than buying a like-for-like replacement. If the lock is cheap or worn, replacing wins.
I've just moved house — which do I need?
Either works, because the goal is just making old keys useless, and you have no idea how many are out there. On uPVC I'd fit new cylinders, because for the same money you can move up to a 3-star anti-snap at the same time rather than inheriting whatever the last owner had.
Someone broke in by snapping the lock. Rekey or replace?
Replace, and don't go like-for-like. Rekeying a snapped cylinder isn't possible, and fitting the same grade again leaves you with the weakness that let them in. This is the clearest case for a TS007 3-star.
Can I have one key for the front, back and garage?
Yes — that's called keyed alike, and it's worth asking for while someone is already there. Doing all the doors in one visit costs less than three separate callouts, and you stop juggling a keyring.