Good advice. But then, just tell them to automatically duck unless they already know the reason why they must play ace (setting trick, or get in to return partner's suit or some such valid reason). Agree. The rule I go by is: duck promptly, unless I have a specific reason to go up that I can clearly explain after the hand ;) Chant after me (it is a mantra after all ;) ) "Second hand low and don't be slow" I agree with your reasoning for when to snatch an ace. Players should be ready when declarer leads any suit in which you hold an ace and are in second seat. This is the essence of planning the hand.