Honestly, cost per wear per item is less important to me than the total amount I spend on my clothes. I track the latter (to the penny!) but not the former.
I have items I paid a lot for but don't wear very often and that's okay because I love them and they are perfect when i do wear them.
I have items I paid very little for that I wear all the time, and that's the best case scenario, of course.
I have items I paid a lot for and wear all the time, and that's great, too. (I'm looking at you, pink patent leather pumps with rainbow heels!)
The ones that sting a little are the ones I paid a lot for that turned out to be wardrobe orphans, but that's part of the process and I try not to let it get me down too much. No guts, no glory, right? If I can, I will eBay them and try to recover some of the cost.
Honestly, the ones that bug me the most are the cheap items that I bought because they were cheap. They end up as orphans and clutter and I am on a mission to minimize that category as much as possible!
I have had a tendency in the past to try and "spread the love" by wearing things just to be wearing them, not necessarily to decrease cost per wear, but to avoid admititng mistakes or whatever. I'm getting away from that and wearing my favorites more and more.