Generally speaking, there are several situations that call for the changing of locks on a building or structure. One of the most obvious times when locks should be changed on a building is when keys have been misplaced, lost or stolen. Changing the locks quickly and without delay will ensure that the safety and security of your building or structure will not be compromised. Protecting property and occupants of a building means ensuring that the locks and associated keys are not compromised or in the wrong hands. One of the best ways to make certain of this is to always have locks changed when there is any question or doubt with regard to the keys that are in circulation.