Yes! I've really been thinking about that a lot.
I think of breaking it down as, is this a weekly-wear item (shoes might be more than weekly)? Or is it biweekly? or only monthly? And is that for all 12 months or one or 2 seasons (hot summer or mid-winter). Plus, is it theoretically weekly ( a great pair of black pants!) but I've got several similar so I really am not wearing any one of them weekly. Then, is it just for one year? Does it look like it'll still be in the picture for 2 years? What items really go on to a 3rd year?
That really sets up the math, and then add the item price.
The most telling part of the equation is, do I have things that fill the same bill and so I'll never wear one or the other enough. ("Enough" being debatable, of course.) I don't worry as much about having some special occasion or dress up items at the ready.
So, I've had to pause over several items that I really do "love" (and bought).
I think it's quite easy to fall into something I might only wear a dozen times in one year and so could have a high CPW unless it has real staying power and is used for 2-3 years
I tend to get excellent "wear times" out of comfortable shoes, most pants (because I wear pants so many days of the week, year-round), lighter weight jackets or trenches, and some of my simpler T-tops. Tops & blouses turn out to be tricky because I think overall I collect too many and am not asking the key question... if I get this new top, usually in order to wear it often, I have to not-wear some other top, so what top will I stop wearing and why? (ergo, good questions from YLF'ers on, are my sweaters I posted too similar--are they too much dupe's).
It's not all just a CPW calculation. Not saying that. In particular, I don't think it's important to judge any individual item on CPW. But the math is such that it becomes quite costly to maintain a large wardrobe of good quality pieces bought at retail prices if the items generally become outmoded in one year or so. Whatever your budget, it is reached by some combination of: actual numbers of items; purchase price; and longevity ( rate of turnover).