In answer to your question, I never used the language of "10" until YLF but I immediately and viscerally understood it as most of the other posters have described. My 10s are the things I love, love, love, love to wear. Ideally, that would be all of my clothing! And I am getting pretty darn close to that these days.
So this is totally emotional -- but the emotion is grounded in something. Usually it's a combination of factors. Fit, flattery, practicality, and perfection for my personal style.
But things change. Clothes start to wear a bit, lose their crispness. Or maybe I change -- my style direction, or my needs, or my body. And fashion evolves, so if part of my joy in clothing derives from being modern, trendy, or cutting edge (which of course are quite different, but related) the item I love most this year might not be my favourite next year. But it's still useful. I stlil wear it. So it's an 8 or so.
Anything less probably isn't worth keeping, in my view. Except for sentimental reasons.
I don't really understand the concept of splitting wears and had never heard about it in those terms. It sounds like she is talking about over duplication? I see no problem with duplicates of essentials that form the foundation of your style -- if you like to repeat. But it does seem crazy to have five identical things.
As for how you reach your target "just right" amount -- I am going at it by feel. Coming at if from the opposite end from you -- I started with basically nothing and have been building. My closet has been growing slowly, even though I am a frequent purger with regular small edits and seasonal culls.
I did try out one of those lists found somewhere or other on the web -- I think on a sewing site -- about what a reasonable seasonal wardrobe might include (not specifics, but number of TYPES of item) -- but I found it pretty useless in the end. I think the only way to figure out what you truly need is to keep track of what you wear and how you feel about that.
For example, last winter I estimated that I'd need a certain amount of knits. And I bought a bunch of new ones (and wore my older ones, also). But it was a really long winter -- and a good knit season -- and I wasn't wearing shirts and blazers as often. So I needed more sweaters for variety in our crazy long winter. Another year might have different weather, different commitments, different offerings. And I might choose differently.
As a general thing, we've talked her about wardrobe size. You can go anywhere from ClearlyClaire's 10 item closet to 33 per season (give or take..."season" divided as you wish) and call that "minimal." Most people would probably say that 100-150 items is "moderate." And over that, "large." But it's totally arbitrary. And also, whether a person lives in a one season or four or six season climate is relevant.
Which doesn't help you a whole lot, I recognize.
I would just ask yourself -- how much do you feel you WANT?
Thistle's "hanger turning" method also sounds like a great idea. I haven't tried it because my wardrobe's so small I can see clearly what I'm wearing and not wearing.
One small caveat -- if you do start editing, don't forget that you're not always in your current season. This is something I have a really tough time with. I completely forget that I actually have a huge need for certain items -- when the temperatures are a certain level! I don't know what gets into me, but if I'm not wearing it NOW, I sometimes imagine that I NEVER wear it -- when in fact it is a workhorse for two or three months of my year.
