Most people do not think about a spare key until the moment they need one, which is usually the worst possible moment to start thinking about it.
The short version: yes, have a spare. An emergency locksmith call-out costs considerably more than cutting a key, and takes considerably longer. But where you keep it matters far more than whether you have one, and the most popular hiding places are the ones burglars check first.
Why a spare is worth the ten minutes
You will eventually lock yourself out. Door pulled shut with the keys on the hall table. Key snapped in the lock. Keys left in a coat, a taxi, a gym locker, a coat pocket in another country. It is not a question of whether but when.
Somebody will need to get in when you are not there. A cleaner, a dog walker, a contractor, a family member checking on the house while you are away, a neighbour dealing with a leak. All of these are easier with a plan than with an improvised phone call.
An emergency is a bad time to improvise. If a pipe bursts or an alarm goes off while you are three hundred miles away, the difference between someone being able to get in and not is the difference between a mopped floor and a ceiling coming down.
That is the case for having one. Now the part that actually matters.
Where not to keep it
These are the places thieves check, in roughly the order they check them.
Under the doormat. Everyone knows. It takes four seconds.
Under a flowerpot or a rock by the door. The second place everyone knows, including the fake rock sold specifically for the purpose, which looks exactly like the fake rocks in every catalogue.
Above the door frame or on the lintel. Standard.
In the letterbox or on a string through the letterbox. Reachable with a hand or a bent coat hanger.
Under the wheelie bin, or inside it. Also standard.
In an unlocked outbuilding, shed or porch. If the outer door is not locked, you have simply moved the key.
On the car's wheel arch or bumper. A magnetic key box on a vehicle parked on a driveway is worse than useless, because it associates the key with the house it belongs to.
A hollow ornament or a hide-a-key that looks like a hide-a-key. If you bought it from a shop, someone else has seen it.
One general principle: if a stranger standing at your front door could find your spare key within a minute of casual looking, it is not hidden. It is stored.
Where to keep it instead
In rough order of how much protection they offer.
1. With a person, not a place
The simplest and best answer for most households: give a spare to someone you trust who lives nearby. A neighbour, a relative, a close friend within a short walk or drive.
There is no hiding place to find, no code to leak, and no hardware to buy. The downsides are real but manageable: they need to be reachable when you need them, and you should reciprocate rather than treating it as a favour.
Do not label it with your address. If that keyring is lost, you have handed someone a key and a map.
2. At work, or in a bag you always have
A spare in a desk drawer, a locker or a work bag covers the most common scenario, which is being locked out during the day.
3. A properly mounted key safe
If nobody nearby can hold a spare, a wall-mounted key safe is the reasonable option. Not a shackle box hanging from the door handle: a unit screwed into brick.
If you go this route:
- Mount it out of sight from the street, at the side or rear
- Screw it into masonry, not timber trim, and use the fixings supplied
- Look for a certified model. Some insurers care, and certification is standard for care and medical access schemes
- Change the code periodically, and always after a contractor or cleaner stops working for you
- Do not put anything identifying inside
4. A smart lock with a mechanical backup
Keypad and app-operated locks remove the spare key problem for daily use. Keep a physical override key somewhere sensible anyway, because batteries fail and phones die.
What about the front-of-house key safe you see everywhere?
You will notice small lockboxes on doors all over any city with a rental market, and it is fair to ask whether you should just do the same.
Two things worth knowing.
It advertises the property. A box on a front door signals that the house is not permanently occupied and that a key is a few feet away. That is a reasonable security concern, and some insurers take a view on it.
In some places it is now a compliance issue. Several European cities have started enforcing rules against key boxes attached to public property. Rome began removing them from railings, gates and façades in January 2025, with fines around €400 per device. Florence acted on similar grounds, and Milan introduced its own prohibition on devices on public land from January 2026. Those measures target devices fixed to public surfaces and protected façades, not the idea of keeping a spare, but if you live in a historic centre it is worth checking before you drill.
For a private home, on your own wall, out of sight, none of that applies. Just do not put it on the front door because everyone else has.
Practical housekeeping
Cut two spares, not one. Give one away and keep one somewhere sensible. Spares get lost.
Test the spare before you need it. Cheap key cutting is genuinely inconsistent, and a spare that does not turn is not a spare. Try it in the lock the day you get it.
Keep a note of who has one. A short list on your phone. When someone stops needing access, ask for it back.
Rekey when the list gets vague. If you cannot say confidently who holds a key to your house, a locksmith rekeying the cylinder is cheaper than a burglary and much cheaper than a new door.
Do not put your address on the fob. Ever. If you want it findable when lost, use a phone number or a tracker instead.
When one spare stops being enough
Everything above assumes one home and a handful of trusted people. If you have started managing access rather than just keeping a spare, the problem changes shape.
The signal is not the number of properties. It is when you can no longer answer two questions: who currently holds access, and who came in last week.
A spare key under a neighbour's care answers both easily. A code shared with three cleaning companies, a handyman, a letting agent and a rotating set of guests answers neither, because a mechanical box cannot tell people apart and cannot keep a record.
That is the point at which keys stop being a household matter and become infrastructure. It is what Keycafe exists to handle: access granted to a named person for a set window, recorded on collection and return, and revocable in seconds without changing a lock.
For one house and one spare, though, the honest answer is simpler. Cut two, give one to a neighbour, and do not put it under the mat.
General information only, not security or insurance advice. Check your home insurance policy before installing a key safe, since some insurers have specific requirements. Rules on attaching key storage devices to buildings and public property vary by city and have changed recently in several European historic centres.
