Problem and Solution: Clothes organization

I'm a bargain shopper. I love end-of-the-season clearance shopping and second-hand store shopping. I almost NEVER buy Killian clothes at full price. I just can't- not how fast kids out grow their clothes, and Killian doesn't even outgrow his all that fast. He definitely gets a good 6-9 months out of each size. Sometimes he gets 2 seasons out of the same set of clothing (such as coats). But still, I like to get a good deal. SO, every season I find that I have bought too many pants and shirts. It happens. I always forget what I already have and keep buying them at good prices. Then I get frustrated when I feel that he's not getting enough wear out of each outfit. So...

Problem: I tend to pick the same shirts and pants for Killian to wear, and neglect the other stuff. Which upsets me since I bought them.

Solution: The solution is 2-fold. 1. For the items in his dresser (PJS and pants). I can fold them up in stacks of 2's. Then, I use the pants from left to right, top to bottom. When I wash pants, I put them in the dresser on the farthest right hand side. So that way they get used in order. So if his dresser is full, I'll use the top pants on the far left first, then the bottom on the far left. Then I push everything over leaving a space on the far right and continue using the pants on the left. As I wash them, I put the on the right. That way I'm not using the same pants over and over. I do the same for his PJ's, though I let him pick them out. I simply put the washed pjs on the bottom of stacks so he can't see them, and he'll pick the top PJS.
2. For clothes that get hung in the closet (shirts, sweaters). I just came up with this solution. I was going to do something similar to the pants, work from left to right. However, I like to have his clothes hung by category- long sleeve tee's, sweaters, button up shirts, sweater vests/ vests, and finally t-shirts (summer items are all on the right hand side of the closet and during the summer, winter clothes get moved over). SO, if I wanted them hung by category, but still  know which ones have been worn most frequently, I'd have to be doing 5 small left-right organizations and that was just too much. SO, my new solution: different colored hangers. I have both blue and white hangers, but just grabbed them as I needed. NOW, I have all his shirts/sweaters/etc. on blue hangers. As they are used and washed, they get put on white hangers. Then, I'll know to use the blue hangers first. Once all shirts are on white hangers, then I'll start putting them on blue again. It's working great. Of course since he has more sweaters than long sleeve tee's, those get used more often. However it is forcing me to put him in his button-up shirts more often as well.

SO, that's my solution. Left-right usage in drawers and different colored hangers in the closet. Of course, at some point I'll have to come up with a system to stop over-buying. I've thought of making a print-out of all the items I have in storage, but I can't very well bring that along with me shopping. Any suggestions?