I don't track CPW. As I see it, most folks use CPW to either spend higher than they're accustomed to ("it's going to be a workhorse") or to purge an item ("I've gotten my value from this piece").
I need both, but do it in a slightly different manner. I keep an outfit log, and I set and stick to both a budget and a one-in-one-out policy. Lastly, I don't purge an item until it's completely worn out, and if it's a workhorse I'll do my best to make that item last as long as possible.
Waiting until an item is worn out means I feel good (enough) about purging items that I don't need CPW to justify the purge. Unfortunately, it also means that I have a "hitlist" of items that I'm ready to purge but haven't worn out yet. This is where the outfit log comes in; I have a list of almost-fab outfits that I can draw upon to wear out the unfab item faster.
The budget and one-in-one-out policy keeps me laser-focused on the items I bring in -- I'll typically have contemplated it for a season (and the outfit log is used to justify its usefulness in my wardrobe!) and had to shuffle things around in the budget to do so.
My entire complicated system hangs together only because I live in a climate with almost-indistinguishable seasons and because my style is minimal modern classic: I don't need to jump on trendy items, but I do need items that look great in a minimal outfit (which requires a lot of sleuthing), and I can wear my items almost year-round.
