I don't know how most writers work. For me, novel ideas have to roll around in my head for months and sometimes years. And I work on them in spurts on my computer. I might do the initial brainstorming and save it in a file folder with that novel's name and the year.
Then I'm likely to put it aside for months and years while I work on another project. Then I brainstorm some more, save it in a file, put it aside for another project and so the rotation goes.
The end result is that I end up with a file on my computer filled with tons of different documents---various spurts of manuscript, different versions of chapters or scenes, research files, brainstorming sessions where I puzzle out the GMC of my characters, etc. It makes for a LOT of files.
Now that wouldn't be so bad if you are working on that manuscript from start to finish with no breaks. But when you take detours and come back to the material months later, you can no longer remember which version you'd settled on, which scenario you wanted to use, etc. Even your brainstorming notes from months ago don't make much sense to you any more.
So you are left with heaps of files to go through, sort, and try to figure out what to keep and what to toss.
I am going through this right now. Last year, I completed what was novel #2 in a series. Now I am preparing to go through and get back to work on novel #1 in that series. And what a mess I came back to! As if I had time to waste sorting and trying to organize all the material I'd compiled previously.
If this has happened to you and you found a solution for this problem, I'd love to hear from you.
I don't know if its the best solution, but I have decided that for 2011, once I sort and organize all the data, I am going to have only two files for this novel---one for actual manuscript in progress, the other file for all the brainstorming, research, and miscellaneous notes.
I can't think of any other way to keep it manageable.
If you have ideas or advice, please share!