For various reasons, the rules instruct you to deplete a card. You do this to indicate the card has been used this turn. Whenever you are instructed to deplete a card, you must indicate the card has been depleted in a way that is clear to you and your opponent. Once a card is depleted, it cannot be depleted again until it is restored. Resources do not deplete. Instead, they are attached to your faction. (see Paying Costs)