I have adopted a minimalist approach with respect to practice strokes...I pause at the cue ball, pull back, pause and stroke. I do two slow distance-measuring strokes as soon as I get down, but not a lot of sawing back and forth. For a long time I would ensure at least 4 practice strokes, but came to the conclusion (for me) that it was wasted effort--and actually broke my concentration. I need at least one measuring stroke to check that my stance is straight and nothing's binding or pulling my stroke off line. But in my PSR the most important/useful part is the pause at the cue ball. It lines up my vision and visualization of the shot (I actually view the results of the shot in my mind's eye during this pause, then pull the trigger).
I wanted to quote this message because I think some people are missing the point in the discussion about practice strokes, or at least a part of the point.
I mentioned the difference between the traditional practice stroke and the cue ball - cue tip measuring that some players do in a previous post. West Point described it better than I did here.
I don't know of any players that just get down and shoot. Sean mentioned Tony Drago. He does the measuring thing where he just sizes up where he's going to hit the cue ball. Ronnie O'Sullivan pretty much does this exact same thing, except he might throw in a single practice stroke, of the sawing variety.
For me personally, I do just as West Point 1987 described, I might do 1 practice stroke after I first approach the cue ball just to loosen up, but then I just focus on where I'm going to hit the cue ball. I've found this focus on the cue ball/cue tip contact is WAY more important than trying to gauge the speed of the actual stroke.
Ever since I've thrown the traditional practice strokes out I've noticed that I'm playing much more subconsciously. Of course, I've noticed that after the fact, not while I was shooting since that wouldn't be possible right???
I think this is one of those things that will definitely vary from player to player but it's worth messing with if you are like me and you think maybe you are spending too much time down over the ball.