The game is precise about when things happen; you can’t just do them whenever you want. You can’t heal someone between turns, because you can’t do anything between turns. You can’t play Revitalize before advancing the hour just to get the advantage that Sarenrae’s Light provided on the previous turn. You can’t play a Cure spell during a combat check, or during recovery, or right before a Dragon bathes you in flame. The cards will tell you when to play them, so follow their lead.