Paperwork is one of the toughest forms of clutter to vanquish. Often, it’s much more anxiety-provoking and draining than going through a clothes closet or a desk drawer. To decide what to keep and what to toss, ask: Do you actually need this piece of paper or receipt? What specific use does it serve? Have you ever used it? If you’ve never referred to a category of paperwork, apparently you don’t need it. Will it quickly become dated—like travel or…