Keyed Alike, Keyed Differ or Master Keyed?

Do I need my locks Keyed Alike, Keyed Differ or Master Keyed?

Keyed Differ (KD)

Each lock has its own unique key, one which cannot be used in any other lock in the set.

Keyed Alike (KA)

All locks within a set can be opened with the same key. This option is a great time saving solution and beneficial when multiple locks are used by the same person so that only one key needs to be used.

Master Keyed (MK)

In a Master Keyed system, each individual lock can only be opened by a key specifically designed for that lock, however there is also one key that can unlock all the locks in a set (this is a Master Key). Master Keys are beneficial for managers and supervisors to keep hold of if circumstances arise where individual keys go missing or they need to override the system and remove a lockout device.