Keys accumulate quietly. A house changes hands and the old set is never accounted for. A contractor is given a key for a week-long job. A relative keeps one for emergencies. A cleaner, a dog walker, a former housemate. None of it feels like a security problem until you try to write the list down and find you cannot.
The useful thing about rekeying is that it resolves the entire list at once. You do not have to identify every copy in circulation or ask anyone to hand anything back. The cylinder is re-pinned, a new key is cut, and every key that existed before that moment becomes a piece of scrap metal.
It is worth doing at predictable moments: when you take possession of a property, when a tenancy ends, when a key goes missing with anything identifying attached to it, and when the relationship that justified giving someone a key has ended.
- Taking possession
- Assume keys exist that nobody has mentioned.
- Tenancy change
- Rekey between occupants rather than trusting a key count.
- A key goes missing
- A replacement key does not disable the lost one. A rekey does.