Plenty of lock work is genuinely within reach of somebody competent with tools, and some of it reliably goes wrong. Here is an honest line between the two, from people who are called out to fix the second category. Where this page is the considered account of the line between a job you can do and one you should not, locksmith near me is the version written for the pavement.
Not every locksmith call is necessary — but some jobs regularly turn into an expensive rescue.
OK to DIY
Padlocks, letterbox locks, cupboard locks.
Borderline
Yale-style rim-latch swaps if the door is in good shape.
Get a pro
Mortice locks, multi-point locks, security gates, safes.
What is genuinely straightforward
Replacing a cylinder in an existing mortice or euro-profile lock is, on a door that is behaving, a fifteen-minute job with a screwdriver. The dimensions have to be right and the cylinder must not protrude beyond the handle or escutcheon, but there is nothing mysterious about it and no reason a competent person should pay somebody else to do it. If this is the part you are stuck on, how to tell if a lock needs replacing takes it further.
Changing handles, fitting a door viewer, adding a second fastening above child height, replacing a padlock or fitting a hasp are all in the same category. So is adding a bolt to the inside of a door. These are ordinary fixing jobs where the main risk is drilling in the wrong place, and the worst outcome is cosmetic. There is a separate article on how to choose a locksmith if that is closer to the problem in front of you.
Lubricating and cleaning a stiff mechanism is also reasonable, with the caveat that the right product matters and less is better. If a mechanism improves noticeably with a clean and a light lubricant, that was the problem and you have saved yourself a call-out. If it does not, stop — because at that point you are working on something with an actual fault.
Where it reliably goes wrong
Anything involving the frame. Moving a keeper, fitting a strike plate, correcting a door that has dropped — these look like carpentry and they are the parts that decide whether the door resists anything at all. A keeper fixed into a few millimetres of timber, or repositioned by eye, produces a door that closes beautifully and gives immediately, which is the worst combination available.
Fitting new hardware to a door that has never had it. Cutting a mortice, drilling through a stile, positioning a lock case in a door of unknown construction — those go wrong in ways that cannot be undone. Modern composite and aluminium doors in particular have structure and cavities that are not visible from outside, and an error there frequently means a new door rather than a new lock. A Randburg locksmith sees the line between a job you can do and one you should not more often than most trades would guess.
And anything on a door that is already misbehaving. Fitting new hardware to a door that binds, sticks or has dropped guarantees the new hardware misbehaves too, and the household then concludes the product was bad. The door was the problem before and it is the problem afterwards, and that is a diagnosis job rather than a fitting one.
The three checks before you start
Does the door sit square in its opening, and does the bolt drop cleanly into the keeper with the door closed? Work the mechanism with the door open and then with it closed. If it behaves differently, the door is out of true and no amount of new hardware will fix that. Deal with the alignment first or accept that the new lock will behave exactly like the old one.
Is the keeper fixed into something solid? Take the plate off and look. On a great many doors the screws reach nothing more than the door lining, and a lock resisting force is only as good as what the bolt lands in. This is the single most under-examined component on any door and the cheapest one to improve.
And will the new cylinder sit flush? A cylinder that protrudes past the handle or escutcheon can be gripped, and a gripped cylinder can be broken quickly and quietly. Getting the length right is not difficult and getting it wrong is the commonest error in domestic lock replacement — a new lock, correctly fitted, that is easier to defeat than the old one. Readers who came here for residential locksmith work will find it set out properly on its own page.
The economics are not what people assume
The saving on a straightforward cylinder swap is real and it is small in absolute terms. The cost of a job that goes wrong is not small: a drilled-out lock, a damaged door, a frame that has to be made good, and then the original work done properly anyway. That asymmetry is why the line between the two categories matters more than the hourly rate does.
There is also a hidden cost that nobody prices in, which is the door that ends up working badly and stays that way for years. A household that has fitted something themselves is understandably reluctant to call somebody about it, so a lock that needs a shove becomes permanent. That is how a lot of the doors we eventually see got the way they are.
Where several openings need doing, the calculation changes again. Doing four doors in one visit costs meaningfully less per door than one, which means the DIY saving on a whole-house job is proportionally much smaller than on a single cylinder. If the plan is to do the reachable openings after a purchase, it is worth a quote before deciding.
Buying the part is half the problem
Measuring a cylinder correctly is not obvious. It is measured from the centre fixing screw outwards, and the two halves are frequently different lengths — which is why a great many self-bought cylinders end up protruding on one side. Take the old one out and measure it, or take it with you, rather than estimating from the outside of the door.
The other trap is buying for appearance. A fitting chosen because it matches the handles, on a door that takes weather or heavy use, will not last. This matters most on outdoor and gate hardware, where sun, dust and driven rain finish anything that was specified as an indoor part — and on a busy door, where a domestic fitting simply wears out. We keep a full account of car locksmith work separately, since it raises its own questions.
It is also worth knowing that we will fit hardware a customer has bought, and will say beforehand if it is wrong for the door. That is a reasonable arrangement for anybody who wants to choose the part themselves without taking on the fitting. What we will not do is fit something under-rated and stay quiet about it, because we would rather not be back.
When to stop and ring somebody
If a screw will not come out, if the mechanism will not release from the door, or if something has to be forced to move — stop. Those are the moments where a routine job turns into a damaged door, and the difference between stopping and continuing is usually about ninety seconds of impatience.
If the door has to be closed for the night and the work is not finished, stop earlier than that. A property left insecure because a Saturday project overran is a genuinely bad outcome, and it is entirely predictable by mid-afternoon. Better to fit the old hardware back and finish another day than to improvise something at seven in the evening.
And if a key has snapped, if something is stuck inside a mechanism, or if a cylinder has been partly drilled, that is now an extraction rather than an installation. Attempting the rest with pliers is the step that decides whether it stays a small job. At that point a straightforward lock repair or lock change visit is the cheaper path.
A reasonable division of labour
Do the cylinder swaps, the handles, the door viewers, the padlocks, the extra fastenings and the cleaning. Those are ordinary household jobs and there is no reason to pay for them. Buy the parts yourself if you want to, measuring properly and choosing for the position rather than the appearance.
Get somebody in for anything involving the frame, the keeper, a new mortice, a door that already misbehaves, or a whole-house job where the per-door cost drops anyway. Those are the ones where the failure mode is expensive and permanent rather than annoying and reversible. If an emergency locksmith visit is closer to what you need, there is a full page on how that side runs.
That split gets a household most of the saving and almost none of the risk. It also means that when somebody does come out, the job is the actual problem rather than an undoing of a previous afternoon — which is faster, cheaper, and considerably less irritating for everybody involved.
Knowing when to stop
If a screw will not come out, if the mechanism will not release from the door, or if something has to be forced to move — stop. Those are the precise moments a routine job becomes a damaged door, and the difference between stopping and continuing is usually about ninety seconds of impatience. Nothing is lost by putting the old hardware back and finishing another day.
Stop earlier than that if the property has to be secure tonight. A house left insecure because a Saturday project overran is a genuinely bad outcome and it is entirely predictable by mid-afternoon. Refitting what was there and booking somebody is the cheaper decision, and it is the one most people take too late.
And if a key has snapped, if something is stuck inside a mechanism, or if a cylinder has been partly drilled, the job has changed category: it is now an extraction rather than an installation. Attempting the rest with pliers decides whether it stays small, and at that point a straightforward lock repair or lock change visit is the cheaper path by a wide margin.