I hear all the time about multiple runtimes but admittedly I am unsure of the logistics of pulling it off.

If I have a single runtime that is already filled with items am I able to easily split that up or organize it into sub categories without affecting saved files?

I am a Poser novice and know very little about its inner workings so I don't know if saved files are calling to certain paths to load the items used in them or how these things work. I'd just like a little advice before I go rearranging files and creating huge head aches for myself when I reload old saves.

I did search the forums but couldn't really find an exact answer to my question that clarified things to my satisfaction.