When is it acceptable to change a combination?

• A. When a door is repainted
• B. When a calendar year passes
• C. When a key is lost
• D. When a lock is taken out of service

Answer: (D)

Changing a lock’s combination is a security step used when you are retiring or decommissioning a lock. If a door or lock is taken out of service, you want to ensure that any existing keys no longer work, so updating the combination (or simply deactivating the lock) is appropriate. Repainting a door or letting time pass doesn’t affect the locking mechanism or access codes. While losing a key triggers security actions, the explicit scenario that calls for changing the combination in this context is when the lock is being taken out of service, to prevent any future access by old keys.