Most steel cabinets that lock come with two keys, and while you can reasonably use that second key as a backup, you might decide to give the key away to someone else. Often, it should be someone who needs access to the cabinet just as badly as you do, or perhaps a staff or family member that you trust. Just make sure they don’t lose the key, and also make sure that you are keeping yours with you at all times. No one ever wants to need to get into the cabinet and then not have the key! That’s just embarrassing, and can also make a bad situation worse as you try to break into your own cabinet!