A spare key goes missing, a tenant moves out, or your front door starts sticking for the third time this week. Those are the moments people start asking when should you change locks, and the honest answer is that it depends on risk, not just age. Some situations need a full lock change straight away. Others can be dealt with by repair, adjustment or rekeying, depending on the door, the lock and who may still have access.
For most homes and small businesses, the right decision comes down to one simple question: are you still confident that only the right people can get in? If the answer is no, changing the locks is often the safest and simplest step.
When should you change locks after moving in?
If you have just moved into a house, flat or commercial unit, changing the locks is usually sensible. It is not about assuming the previous owner, tenant or tradesperson would do anything wrong. It is about the fact that you cannot know how many keys are still in circulation.
Estate agents, cleaners, dog walkers, neighbours, previous tenants and family members may all have had copies at some point. Even if everyone involved has been perfectly trustworthy, keys are easy to forget about. A lock change gives you a clean start and removes that uncertainty.
This applies just as much to landlords and holiday-let owners. Whenever occupancy changes, access control matters. If guests, former tenants or contractors may still hold keys, replacing or rekeying locks can be the more responsible option.
Lost, stolen or unreturned keys
This is one of the clearest answers to when should you change locks. If keys have been lost and there is any chance they could be linked to your address, changing the locks is worth serious thought.
If you dropped a key somewhere random and there is nothing identifying where it belongs, the risk may be lower. If a handbag, set of keys or work keys were stolen along with ID, business details or paperwork showing your address, the risk is much higher. In that case, a prompt lock change is usually the right move.
The same applies when keys are not returned after a relationship breakdown, a change of tenancy or a staffing issue. People often hesitate because they want to avoid confrontation or cost, but uncertainty about access tends to linger. A lock replacement gives certainty back.
After a break-in or attempted burglary
If your property has been broken into, damaged during an attempted break-in, or left insecure after forced entry, changing the affected locks is often necessary. Even when the lock still appears to function, internal damage can leave it weaker than it looks.
There is also the issue of confidence. After a burglary, many people want to know their property has been properly secured, not patched up in a hurry. That may mean replacing the damaged lock, upgrading the standard of lock, or addressing weaknesses in the door alignment or frame at the same time.
This is one area where the cheapest option is not always the best one. A damaged lock might turn, but if the mechanism, keep or cylinder has been compromised, replacement is the safer call.
If the lock is worn, unreliable or hard to use
Not every lock change is about security after an incident. Sometimes the warning signs are more ordinary. Your key may stick, the handle may feel loose, the lock may only work if you lift the door, or you may need to jiggle the key to get it to turn.
That does not always mean the lock itself has failed. On uPVC and composite doors in particular, poor alignment can put strain on the mechanism and make a working lock feel faulty. In those cases, adjustment or repair may solve the issue without a full replacement.
Still, if the lock is genuinely worn, becoming inconsistent, or failing more often, it is better to deal with it before it leaves you locked out or unable to secure the property. Locks rarely improve with time.
When should you change locks instead of repairing them?
This is where a lot of people need clear advice. Not every problem calls for a new lock. If the issue is minor wear, door misalignment, a loose fitting or a part that can be replaced safely, a repair may be the better value option.
A change is more likely to be the right answer when the security has been compromised, the lock is obsolete, the mechanism has failed internally, the correct key control has been lost, or the existing setup no longer suits how the property is used.
For example, if a rental property changes hands and you do not know who still has keys, replacement makes sense even if the lock works perfectly. If a business has a lock that still functions but no longer meets insurance or access needs, changing it may be more practical than trying to keep an old setup going.
A good locksmith should tell you honestly which route makes sense. If a repair is enough, that should be said plainly. If replacement is the safer long-term option, you should know why.
Landlords, HMOs and short-let properties
If you manage property, the question of when should you change locks comes up more often. Turnover creates access risk. So do staff changes, contractor access and lost key reports that are difficult to verify.
For landlords, there is a balance between security, tenant rights and cost. You should not change locks in a way that breaches tenancy rules, but between occupancies it is often wise to review who may still have access. In HMOs and short-lets, where multiple occupants and frequent key handling are common, lock changes or cylinder changes can be part of sensible property management rather than a last resort.
It is also worth thinking beyond the main front door. Patio doors, back doors, garages, side entrances and internal office doors are often overlooked. Security only works if all practical access points are considered.
Staff changes and small business security
For small businesses, lock changes are often triggered by staffing changes, missing keys or changes in premises use. If a former employee had unsupervised access and keys were not recovered, replacing the relevant locks is often the safer choice.
There are cases where a restricted key system, digital access control or a better master key arrangement may be more suitable than repeating standard lock changes every time someone leaves. But if you need an immediate answer, and control over keys has been lost, changing the locks is usually the fastest way to restore control.
Do old locks always need replacing?
Not necessarily. Age on its own is not the only test. Some older locks continue to work reliably and securely, while some newer ones fail early because of poor installation, frequent use or door movement.
The better question is whether the lock is secure, reliable and appropriate for the door. If it meets current needs, operates properly and has no known access risk, there may be no urgency. If it is causing trouble, showing signs of weakness or leaving doubt about who can enter, replacement becomes easier to justify.
That is why a proper assessment matters. Changing locks too quickly can waste money. Leaving them too long can create avoidable risk.
What to do if you are unsure
If you are not sure when should you change locks, start with the reason you are concerned. Has access control been lost? Has there been damage? Is the lock unreliable? Have occupants changed? Those details usually point towards the right solution.
In many cases, a locksmith can tell quite quickly whether a repair, adjustment or replacement is the sensible option. The key thing is getting straightforward advice before any work starts, along with clear pricing and a realistic explanation of what needs done.
That matters most when you are stressed and need a quick decision. Whether it is a family home, a rented flat, a holiday let or a small shop, good locksmith advice should reduce uncertainty rather than add pressure. At Scotia Locksmiths, that means honest recommendations, upfront pricing before travel, and changing locks only when it is genuinely the right step.
If something about your lock or key situation does not feel right, trust that instinct. Security problems are easier to deal with when they are small, and peace of mind is usually worth more than waiting for a lock to fail at the worst possible moment.
Scotia Locksmiths are trusted, local, mobile locksmiths serving the following areas:
Perthshire & Kinross: Perth, Crieff, Blairgowrie, Kinross, Pitlochry, Aberfeldy, Auchterarder, Scone, Bridge of Earn, Kenmore, Blair Atholl, Coupar Angus, Glenfarg, Abernethy
Stirlingshire: Stirling, Dunblane, Callander, Killin, Lochearnhead, Bridge of Allan, Cambusbarron, Doune, Fintry, Kippen
Dundee & Angus: Dundee, Broughty Ferry, Monifieth, Carnoustie
Fife: Dunfermline, Kirkcaldy, Glenrothes, St Andrews, Cupar, Leven, Rosyth, Newburgh, Auchtermuchty, Falkland, Kinghorn, Burntisland, Aberdour, Dalgety Bay, Inverkeithing
West Lothian and Falkirk: Falkirk, Grangemouth, Livingston, Bathgate
Lanarkshire: Cumbernauld, Airdrie, Bellshill, Motherwell, Hamilton, Cambuslang
Clackmannanshire: Alloa, Tillicoultry, Tullibody, Alva, Dollar, Sauchie.