I have maybe 90 runtimes, and I thought that was a lot.

It dates from the days when Poser couldn't show everything if you had too many items on one folder. Plus I just find it convenient. I have stuff sorted by figure (V3, V4, Dawn, LaFemme, etc.), and by genre (SF, horror, toon, contemporary). I also have some runtimes devoted to particular themes - either stuff I do a lot, or stuff I needed for a particular project (Star Trek, politics, sports, for example).

I usually have less than 20 loaded at a time, though. That's kind of the point of multiple runtimes: I don't have to look through everything when I want something.

A different runtime for each item seems excessive.