I've done this as well for my mods as I have a folder for NRass, MTS, skins, pets, vehicles, poses, clothes, items. And in my TS3 Download folder, I have the folders set up for my ATS3 that will have sub-folders for things such as baby/children's room, kitchen, living room. And then the store stuff is labeled as sets in compilations, EA items not in sets, player made Sims, Create-a-Pattern, misc. store items, etc. And once I have installed an item from the store or ATS3 into my game, I move the file from the TS3 download folder to another folder that's located outside of the TS3 folder and then delete the item from the Download folder inside the TS3 folder.