thimbelina, part of it was that I was wardrobe building this year and bought a lot of clothing, (and had little legacy clothing), so I really wanted to see how my new wardrobe size was working for me. Was it too much? too little? How much did I enjoy variety? etc. So I set myself a goal of under 2$ CPW for everything bought this year by the end of the year, and wore things strategically so I had a real sense of how it felt to wear an item often enough to make that goal. Sometimes it felt a bit onerous--it was clear which items were okay but not great, sometimes I quickly flew past a goal and something became a workhorse.
I also found that some high happiness items were going to be difficult to make that goal, so I wanted to see if the overall wardrobe would average that goal. (I also did some cheats, like use income from items consigned to cover part of the price of certain higher priced items to reduce the overall spending).
So I basically totaled the column of my current CPW dollar amounts for each item, and divided that by the number of items/rows. So my number of items bought this year = 125 (eek! I know, I know, does it help that I count tights, shoes and accessories too? basically everything but undies ). Total expenditure = 1,211$, Total of all the current CPW = 102$. So that tells me my average cost per wear near the end of the year is 82 cents, even though some items might be higher and some lower. I want to break this down further by item type in the future - like you say, some categories are easier to reach than others. For me, tights unfortunately actually still have a really high CPW before biting the dust.
It also told me that I wasn't that happy with too much of any one category, buying too many tights, leggings, and tops meant it was a struggle to wear each of them regularly, even with very low initial purchase prices.
ETA: also thinking more about this, I figured I could add up my number of wears and figure out the same thing. Result is that the average number of wears for any one new item so far is 12 wears, for my legacy (previous years) items it's 5 wears. I think this could be more useful to look at per category rather than overall, though it tells me I need to wear or cull more older clothes.
