Do charges have to be expended for all powers on a character card? Or only those powers that specifically say Discharge 1.
e.g. The duelist states
When rolling for combat roll two dice and keep one
Discharge 1 to replace a team member's combat roll with your unused die roll.
Discharge 1 to use the sum of both dice as your combat roll.
Does this mean I can always roll 2 dice and keep, say, the highest one without discharging?