Define the change in access
A missing key, a change of occupant or uncertainty about old copies can make a key change worth discussing. List the doors included and say whether you still have working keys. Identify the people who should retain access after the change.
Rekeying changes the key that operates a suitable cylinder while retaining compatible hardware. Condition matters: a lock that sticks or behaves unpredictably needs its operating problem assessed too. Explain that history rather than treating the new key as a repair.
