If I have 2 apps that I need to use to edit a particular file and I have that file in Documents, I have to "save copy to..." or "send to..." app#1, make changes, send the file back to Documents, and within Documents send it to app#2, and then back to Documents.
That results in 3 copies of the file... in app#1's sandbox, app#2's sandbox, and Documents.
What I do is the other way around. So I open word, open the file I want to work on, save the file (well, word.app auto saves by default). Then I could open the second app and open the same file in the second app.
What specific files/apps is it about?!
Documents is for file/folder-management