Early on, before bidding systems were elaborated in bridge, "quick tricks" provided something of a guide to bidding. For instance, people might open hands with a configuration of AKxxx Axxx xx xx, which had 11 high card points using the Work Count, but pass a hand of Kxxxx Qxxx Qx Ax, which had the same 11 points. The thing in favor of the first hand was that it had three sure "quick tricks."
Suppose I am sitting East, defending a 3NT contract (neither vulnerable, South bid 1NT, North 3NT). West leads a 6 that looks like fourth best (and an examination of my hand and dummy suggests that West probably has a fifth card). I have Axx in the suit, and a side ace, that is two "quick tricks" with 8 high card points. So I win the trick, and lead back a low card, hoping that West has the king, or at least the queen. South plays the king, so I take my side ace at the first opportunity, and lead back my last card in West's suit to his presumed queen. That is what I would call "fast" play, based on my quick tricks.
Suppose, instead, I am sitting East (possibly with the same dummy as in the first example), but I have xxx in West's suit; no help for him. I have eight high card points, distributed in the three side suits as (xxx) Kxxx QJx Qxx. In this latter case, I have no quick tricks, and I play "slowly," trying not to give anything away.
So can "quick tricks" be a useful guide to a defensive posture, as between say, active and passive, or fast and slow defense?