When there is a problem with the lock, such as when it is broken, damaged, or malfunctioning, it is replaced. Locks and keys work in pairs, and if either or both show signs of wear and tear, the system is jeopardized, which is why it is best to have them replaced as soon as possible in such cases.
When key control is lost, such as when you lose them or they are stolen, there is a high risk of them falling into the wrong hands and jeopardizing your home security. In these cases, rekeying works best, rendering the old, lost, or stolen keys completely useless.