I must still have a lot to learn. I usually do a three pass shave because I can see that my shave isn't great after just two. I could skip the middle pass, probably, but that means a greater risk of irritation during ATG. The only time I'll stick with two passes is when shaving again in less than 24 hours, because my face lets me know it isn't appreciated.

Perhaps growth rates and color of hair makes a difference? I have dark hair and fairly light skin, so any growth is clearly visible, and by the end of the day, I can feel stubble. I can't shave at night because I'd have 5:00 shadow when I get up in the morning, so I'd have to shave again anyway.