As a target, I'm shooting for under 2$ within a year of purchasing new clothes as a baseline, under 1$ as a goal.
Part of why I'm placing more of an emphasis on it is because, gulp, I bought around 100 items of clothing this year (this includes shoes, belts, tights, coats, scarves and bags) and I really want to get a sense of how unmanageable or manageable wearing that is.
Halfway through the year, I'm doing well in terms of my CPW goals, but I've discovered that older clothes (about 70 including accessories) are much harder to incorporate and wear because of the sheer amount of new clothes, and so my overall closet needs to shrink a bit more if I want it all to be used. I'm culling older clothes that have done their duty and aren't 10s pretty regularly though.
My takeaway so far is that with a small closet, CPW for some items could be a lot higher initially, because it balances out given time, but with a large closet it's tricker to get even 10 wears in of a 10$ top for instance within a few months just because I have so many. I need to break down items by category more I think and set one in one out limits, that's how I ended up with too many tops, but still having room for growth in the shoe and bag department.
The other thing about tracking wear and cost per wear is it forces me to actually rotate outfits and come up with new ones constantly to increase wears for new items, and to experiment and get creative about how to bring an item into play in another setting or season. In some ways this is artificial, and leads to occasionally wearing okay combos instead of repeating a great one, but I really like it as a discovery and experimentation process.