Bennies may be spent at any appropriate time and don’t incur any sort of penalty. They may only be used on your own character. Here are the ways characters can use their Bennies.
REROLL A TRAIT: Bennies grant a hero a reroll on any Trait, and best of all, you get to keep the best total from all your rolls. The only exception is a Critical Failure, which ends the attempt and must be accepted. Such is the price of tempting fate!
RECOVER FROM SHAKEN: This is instant and may be done at any time, even interrupting another’s actions if desired.
SOAK ROLLS: Bennies can also be used to prevent Wounds or recover from being Shaken. See Soak Rolls on page 96 for more information.
DRAW A NEW ACTION CARD: When the game is in rounds, a character can spend a Benny to get a new Action Card (see page 91). This occurs after all cards are dealt and Edges or hindrances like Quick, Level Headed, or Hesitant are resolved. Then players or the GM may spend Bennies for an additional card as many times as they like and take their choice of all their draws. Edges like Quick or Level Headed do not apply to these additional cards drawn with Bennies. This continues until everyone (including the GM) passes. Then the round begins and no further cards may be drawn.
REROLL DAMAGE: You may spend a Benny to reroll damage. Include any additional dice you may have gained for a raise on the attack roll.
REGAIN POWER POINTS: A character with an Arcane Background can spend a Benny to regain 5 Power Points (Power Points and their use are explained on page 147.)
INFLUENCE THE STORY: This one is entirely up to the Game Master, who may allow your character to spend a Benny to find an additional clue if you’re stuck, come up with some mundane but needed item, or push a nonplayer character into being a bit more agreeable.