The tenant has moved out and returned all the keys—does the lock still need to be changed?

The client's name has been changed. The story reflects a typical situation that arises after the end of the lease of an apartment or other premises.

Let's call the owner of the apartment Martin. Martin rented out an apartment in Tallinn for several years. After the end of the contract, the tenant vacated the premises, handed over two sets of keys to the owner, the apartment was checked, and no conflicts arose.

A new tenant was supposed to move in in a few days. And that's when the question arose:

“I got both keys back. But how do I know that a third one wasn’t made at some point?”

Returning keys does not show the number of existing copies

For most regular mechanical keys, there is no system in place to look up the duplication history. Therefore, the owner may know how many keys he handed over to the tenant, but may not always know exactly how many keys exist now.

This does not mean that the previous tenant necessarily made copies. This is purely about access control.

Do I need to change the lock between tenants?

There is no universal rule. However, from an access control point of view, changing the cylinder between residents has a clear advantage: each new tenant receives a set of keys that is not associated with previous tenants. This is especially true for apartments that were rented out:

• several tenants;
• daily;
• long period;
• together with a parking space or storage room;
• through the management company;
• with the transfer of keys to third parties.

Is it necessary to buy a new lock?

Most often not. For example, if a door has a working cylinder mechanism, only the cylinder can be replaced. The lock body remains the same. The owner receives a new set of keys, and the previous ones stop working.

This is often much easier than replacing the entire door structure.

What if it's a lever lock?

It all depends on the specific model. Some mechanisms allow recoding. Others require replacing individual elements or the entire lock. Therefore, before ordering parts, it is better to first determine the model.

Good habit for a landlord

For owners of multiple properties, it is useful to think of the key as an element of the access system. That is, when changing the user of the premises, check:

• who had the key;
• how many keys were issued;
• whether they are returned;
• whether the combination needs to be changed;
• whether the mechanism itself works properly.

This allows you to simultaneously resolve the security issue and detect a worn lock before a new tenant moves in.