Vendors do include a readme file that lists all the files and where they are located within a runtime.  And for the most part each product is self-contained and you can delete the folders of the product and be rid of it.  However you can run into an issue if the vendor does things non standard.  Not to pick on anyone but Dreamland makes a very nice set of city blocks.  And for Poser each block comes with the same textures in a folder just for that block.  So I have a bunch of the same files that are only useful for the one product, without a bunch of work to unify the materials.  I was reading what he did when he released a set of houses for DS.  There he made the first house with all the textures and if you wanted house #4 you also had to buy house #1 to get the textures.  Makes sense if that you don't fill up your storage with a bunch of redundant texture files, but imagine what would happen if you uninstalled house #1.  All the rest of the houses would be left plain white with no color. 

Poser 5, 6, 7, 8, Poser Pro 9 (2012), 10 (2014), 11, 12, 13