This is an addendum to my previous post.
Before mesh, there were system layers. And like with attachment points, we often got identical items on different layers. Shirts on both underwear (tucked) and upper wear (untucked) and jacket layer, for example.
Most of the older sets are candidate for removal from your inventory. If you want to keep an item in however (I keep some), at least get rid of the extra layers. You can box them for example. I keep only the most relevant and complete layer of an item, like the jacket layer of a top.
While I have my inventory quite under control, I’ve noticed in the past two days that this is an area where I can still gain a massive inventory profit. One of the sets I tossed out contained 80 (80!) system layers in total.
Inventory count now: well below 18k and still going down!