Another little thing is that you can have the same item in multiple places.  For example if a set of expressions goes with a set of poses, you can make a second folder off of the pose folder for the expressions, and keep them in two places.

One thing you have to consider when you put the same thing in more than one place in your Content Library is the fact that each instance of that item takes up memory space on your hard drive. For someone that has a lot of memory to burn so to speak that may not be a problem; but if you are trying to save as much memory as possible (like me), having more than one of anything in your Content Library is not an option that will do that.

As it is I remove much of my 3rd party content and save it in Zip form on my external hard drive. That way I can retrieve it when I need it for something I am working on. And because it is in Zip form it takes up less memory space.

Another thing that I have noted is that many wearable products get made to fit different figures. Like a top made to fit V4, and another version of the same top for say Aiko 3, and yet another for V3, and so on. Now it is possible to make just one fit all figures with a little tweaking; but if you prefer to have each version so you don't have to tweak it for each figure, you can still have just the one texture file for all of them if they share the same UV maps and templates. What I mean is the texture for one version will work with the others that use the same templates of UV maps. So you don't need to have more than one of the same texture for those items. I advise looking into the textures folders for each version to see if the templates are the same. If they are, only put one of each texture into your Runtime folder.