I can't stand how Daz organizes its content, but as soon as I learned that I could relabel folders and move them around just as I do in Poser, it helped tremendously.

As for enormous Poser runtimes, my solution is to have dozens of external runtimes. I now organize by theme; for example: "Greco-Roman", "Medieval - Renaissance", "Post Apocalyptic", "Pirates and Nautical", "Viking", "Reformation - Victorian", "Religion Angels Demons", "Grunge", "Modern War", "Terrain and Vegetation"... and so on.

If it's a small theme with not too much content, I'll put the clothes in as well, for all non-genesis characters. This works for stuff like my "Egyptian" or "Greco-Roman" themes.

If it's a big category, such as "Modern Urban", I'll keep the clothes separate, in a "Modern Urban V4 Clothing" runtime, for instance. 

By the time I'm finished, I will probably have 30 or 40 runtimes. But if I'm not going to be doing any Egyptian or Viking or Roman renders for a while, I'll unlink those runtimes.

My favorite vendors used to get vanity folders. (Now they get their own runtimes -- LOL). I agree with Shane that it's important to know who made what. Also, it helps should you come across a file reference error with textures (which are often put in a folder named after the vendor rather than the product). The others get folder names that include the title of the content plus their name or initials. "Post Apocalyptic Bar - CG" lets me know right away that it's Coflek Gnorg (who, if I had enough money, would have several runtimes all of his own). 

I know... I have way too much content. :D

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PoserPro 2014, PS CS5.5 Ext, Nikon D300. Win 8, i7-4770 @ 3.4 GHz, AMD Radeon 8570, 12 GB RAM.