Rekeying vs changing locks: which one do you actually need?

"Do I need to rekey this or replace it entirely?" is one of the most common questions Australian locksmiths field, and the honest answer is that it depends on why you are worried about the lock in the first place, and what condition the existing hardware is actually in. The two options solve different problems, and understanding the difference makes it much easier to know which one you need.

Rekeying means changing the internal pins inside an existing lock cylinder so that a new key operates it, while the visible hardware — the deadlock body, the handle, the cylinder housing — stays exactly the same. A locksmith removes the cylinder, adjusts the pin configuration to match a newly cut key, and reassembles it, which means any old keys, including copies you don't know exist, stop working the moment it is done. Changing locks, by contrast, means removing the existing hardware altogether and installing a new lock unit in its place — new cylinder, new mechanism, sometimes an entirely different brand or style.

The cost difference between the two is significant, and it is the main reason rekeying is so often the recommended first option. Rekeying commonly costs somewhere in the range of $30 to $60 per lock, since you are largely paying for the locksmith's labour rather than new hardware. Replacing a lock outright typically costs more — commonly somewhere between $70 and $200 per lock for the hardware itself, plus labour, since you are paying for both a new mechanism and the time to fit it. On top of either option, most locksmiths also charge a standard call-out fee, commonly in the region of $80 to $120. For a typical three-bedroom home needing several external locks addressed, an all-in figure somewhere around $300 to $700 is a reasonable planning range, whether that ends up weighted toward rekeying or full replacement.

Rekeying is generally the right call when the existing hardware itself is in good working order and your concern is specifically about who might hold a key — moving into an established home, having lost a key, or knowing that a previous tradesperson, cleaner or tenant was given a copy at some point. In all of these situations, the lock mechanism doesn't need to change, only which key operates it, which is exactly what rekeying achieves at a fraction of the cost of replacement.

Full replacement makes more sense when the hardware itself is the problem rather than just the key situation. Locks that are old, worn, rusted, or damaged are worth replacing outright rather than rekeying, since rekeying a failing mechanism just delays a repair that is coming anyway. It is also the right choice if you want to upgrade to a lock with a higher security rating — for instance, moving to a deadlock genuinely rated to the Australian Standard AS4145.2 for insurance purposes, which is covered in more detail in our article on smart locks versus traditional deadlocks — or if you are switching to a smart lock system entirely. Replacement is also the natural moment to have all the external locks on a property keyed alike, so a single key operates the front door, back door and any side gate, which a locksmith can usually arrange as part of the same job at a modest extra cost.

One detail worth knowing about, particularly if your lock uses a restricted or patented key system, is that some cylinders are specifically designed so that duplicate keys can only be cut by an authorised locksmith with proof you're entitled to one, rather than at any hardware store key-cutting machine. This is a security feature, not an inconvenience — it means a copy made without your knowledge, say by a previous tradesperson, is far less likely in the first place. If you're not sure whether your current lock uses a restricted system, a locksmith can usually tell at a glance, and it's a reasonable thing to ask about when you're weighing up rekeying against replacement, since it changes how much peace of mind rekeying alone actually buys you.

In practice, most locksmiths will look at the actual hardware in front of them and give you an honest recommendation rather than defaulting to the more expensive option — a reputable operator has no particular incentive to replace a lock that only needs rekeying. Getting a firm price for whichever option is right for your situation, along with the call-out fee, before work begins is the best way to avoid surprises. This article is general information rather than a quote for your own property. Our directory lists Australian locksmiths by area if you are ready to compare quotes.

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