First of all, make usage of "folders" as often as possible:
Usually, we do not know in the beginning, how long a document will get over time or how much information will be added in the long run. Therefore, the point where it is necessarily to split the far-too-long document up into smaller parts or to attach other documents (webpages, PDF documents etc.) may come sooner or later. By using a folder, one can add sub-folders and - finally - documents as much and often as one can imagine, without breaking up or creating the entire structure again.
From the opposite point of view: Single documents - called here "pages" (because they represent single web-pages, after all) - should be used only if and when you are "absolutely" sure that there will be not much information added later.
For instance, in the case of this document you are reading at the moment, I feel sure that it would make no sense to have a "FAQ" answered by a very long document that should be split up into several smaller ones. (Usually, then the question itself should be split up into several ones that are easier and short to answer.) Therefore, I think it is sufficient to have a "one-sided" document here in this place - like all the other answers to "frequently asked questions".
[ ... to be continued ... ]