I think I can count on the fingers of one hand the number of times I've worn makeup this year. When I have, it's just been foundation, powder, and lipstick.
Back in high school, I had a full morning make-up routine - foundation, powder, blush, eyeshadow, eyeliner, lipstick. I was 14.
I did need the foundation at times, to cover acne breakouts, but I didn't need the rest of that stuff... but at that age, if you weren't wearing makeup, it implied that your parents wouldn't let you and that you were actually obeying them, and what 14-year-old wants to send that message?
My senior year of high school, I was so hosed with college applications, APs, etc. that my makeup routine slowly got chipped away at. First I started doing eyeshadow and no eyeliner, then I started skipping the blush, then it was just foundation and lipstick, and by the end of senior year I rarely wore makeup at all.
So, I know how to use makeup, how to pick colors that look good on me, how to put on eyeshadow so that it doesn't look like I applied it with a paint roller, etc. - I just hardly ever do it any more.