Is your file cabinet filled to capacity and then some? Instead of going out and buying another cabinet to house your paperwork, first go through your current files to determine what needs to be removed because it's old and outdated, what can be shredded and what needs to be kept. If you haven't referenced that article from the four-year-old issue of Good Housekeeping, I'd wager you can probably toss it.
Given that you can search the internet for pretty much anything and get an infinite number of answers in milliseconds, you may find that much of what you've been saving isn't necessary to keep any longer. And remember, you can always contact me if you need help sorting!