When changing the lock is genuinely the right call
When the lock is worn, damaged or has been forced. When parts no longer exist. When the hardware was never adequate for the door — a domestic-grade cylinder on an entrance that takes real traffic, or a latch on a sliding aluminium door that should have a hookbolt.
And when you were going to upgrade anyway. Doing an upgrade at the same visit as anything else is meaningfully cheaper than arranging it separately, which is why it is worth mentioning even if it was not the reason you called.
When rekeying is the better answer
If the mechanism is sound and the real problem is the number of keys in circulation, rekeying addresses exactly that for less money. The cylinder is re-pinned, every previous key stops working, and nothing about the door changes visibly.
That last point does real work in a development that regulates external hardware. A lock change puts you into a conversation with the estate about finish and approved lists. A rekey does not, because from the outside there is nothing to see.
Landlords, agents and handover days
Keys returned at the end of a tenancy prove very little. Three were issued and three came back, which says nothing about whether more were obtained over three years — for a partner, a family member, a domestic worker. Usually not bad faith; simply ordinary life.
Handover is the cheapest moment to close that question and the easiest to skip. Rekey every external door while the unit is empty, get any gate remotes or access tags deactivated by the managing agent before ordering replacements, and record what was issued to whom. It takes minutes and it is the document that settles any later dispute.
While the door is open anyway
Look at the strike plate. If it is held by two short screws into the door lining, that is the weakest part of the whole assembly regardless of what cylinder you have just paid for. Longer screws reaching the structural stud cost almost nothing and change how the door fails under force.
It is also the sensible moment to deal with the doors nobody thinks about — the back door, the garage side door, the security gate. Those are consistently weaker than the front entrance precisely because they are not the door people look at. See security lock upgrades for what is actually worth spending on.
What it costs, and when to book it
You are given a price band on the phone before anybody is dispatched, and it is confirmed on site against what is actually on the door. The band depends on how many doors, what grade of cylinder, and whether anything has to be ordered — which is why the description you give on the phone matters.
The hour matters too. A lock change is almost never an emergency, and doing it at a booked time on a weekday morning costs less than the same work at eleven at night. Where it genuinely is urgent — a door that will not lock, keys lost with an estate tag attached, a lock that has been forced — it is handled at any hour and you hear the after-hours rate first.
Doing several small things in one visit is cheaper again, because the callout is shared. A change on two doors, a hookbolt on the slider and a look at the pedestrian gate is one morning rather than three, and anything that turns out to be dirty rather than worn is repairing the lock instead.
Doing several doors at once, and why it costs less
The commonest way this job ends up costing more than it should is doing the front door now and the rest eventually. Every separate visit carries its own callout, and on a property with five external cylinders that is four callouts nobody needed to pay for.
It is worth walking the property with the technician at the start rather than pointing at one door and leaving them to it. Half the value of the visit is finding the two cylinders you had forgotten about — the store, the gate onto a service lane, the door between the garage and the house — which are reliably the ones nobody has turned since last winter.
That walk also produces the honest list of what should not be replaced at all. A cylinder that is simply dirty rather than worn wants cleaning, not buying, and saying so is part of the job. Most of what turns up that way is lock repair in Fourways at a fraction of the cost.
The question to settle before anything is ordered
There are two quite different jobs that both get described as changing the locks, and they cost very different amounts. Getting the right one is worth more than shopping around on price.
If the problem is that keys exist which you cannot account for — after a move, after a tenant, after a set went missing — the hardware is not at fault and does not need replacing. Rekeying in Fourways changes the pins inside the cylinders already on the doors, so every previously cut key stops working while the locks, the finish and the handles stay exactly as they are.
Replacement earns its cost in three situations: the hardware is genuinely tired, you want to raise the grade at the same time, or a cylinder was never suitable for the door it is on. If none applies, re-pinning does the same job for less, and a locksmith who does not raise it is not giving you the full picture.
What an estate or complex allows
This matters more in Fourways than in most of Johannesburg, because so much of the suburb sits inside a development that regulates anything visible from common property. Finish, style and sometimes brand are specified, and a few estates run their own restricted key system every unit is expected to join.
Fitting first and asking afterwards is how people end up paying twice — once for the hardware and once for removing it. Ask the estate office or managing agent in writing before anything is ordered, and pass the answer on when you book, because it decides which cylinders can go in.
Where hardware is tightly regulated, re-pinning becomes considerably more attractive since nothing visible changes at all. And the work that is never regulated is the work inside your own unit: a hookbolt on the slider, a reinforced strike plate, a better cylinder between the garage and the house. That is where most of the value sits anyway, and it falls under high security locks in Johannesburg.
What gets carried, and what has to be ordered
Common cylinder types travel on the vehicle, which is why a straightforward change across a Fourways house is normally finished on the first visit with keys handed over on site rather than collected later.
What needs ordering is unusual hardware, older patterns where a modern equivalent has to be matched, and anything satisfying an estate specification. Describing the door on the phone — the shape of the lock, whether the key has a single row of cuts or a track down its face, what the handle does — usually settles which situation you are in before anybody leaves.
Where a part has to come, the door is left secure and working rather than in pieces, and the return visit completes it. That is the standard on an emergency locksmith callout too: nobody is left with a door that cannot lock.
Keying alike, and when not to
Most households in northern Johannesburg carry more keys than they need. A front door key, a back door key, a security gate key, a garage key and something for the estate gate — all different, all on one ring, none labelled, and one of them tried in the dark before the right one.
A lock change is the natural moment to fix that, because the cylinders are being handled anyway and keying them alike costs very little extra at that point. One key opens every external door, the ring gets smaller, and nobody stands in the rain working through five options.
There is a trade-off worth stating rather than glossing over. One key for everything means one lost key affects everything, and anybody handed a key for one purpose can open all of it. Where somebody needs partial access — a gardener who should reach the store and not the house, a tenant in a cottage — the answer is master key systems in Fourways rather than keying everything alike.
The frame, which decides whether the new lock is worth anything
It is possible to fit an excellent cylinder to a door and improve nothing at all, and across Gauteng it happens regularly.
Strike plates are frequently held by short screws biting into an architrave rather than reaching structure behind it. Force going around a lock does not care what the lock cost, and a very good cylinder in a weak frame is bypassed entirely without anybody touching it.
So a lock change should include longer screws reaching the stud and, where warranted, a reinforced strike plate. It adds very little to the visit and it is the difference between a new lock and a genuinely better door. Anything found along the way that is worn rather than weak is lock repair in Johannesburg instead, and it is priced separately.
What it costs, and when to book it
You are given a price band on the phone before anybody is dispatched, and it is confirmed on site against what is actually on the door. The band depends on how many doors, what grade of cylinder, and whether anything has to be ordered — which is why the description you give on the phone matters.
The hour matters too. A lock change is almost never an emergency, and doing it at a booked time on a weekday morning costs less than the same work at eleven at night. Where it genuinely is urgent — a door that will not lock, keys lost with an estate tag attached, a lock that has been forced — it is handled at any hour and you hear the after-hours rate before a technician leaves.
Doing several small things in one visit is cheaper again, because the callout is shared. A change on two doors, a hookbolt on the slider and a look at the pedestrian gate is one morning rather than three. If you are not sure which job you need, describing the symptom to a locksmith in Fourways costs nothing and frequently settles it.