Throw most of them away—yes, even those debit-card receipts, once you’ve verified their accuracy with your bank. The only receipts you should definitely keep are those for purchases that you’re planning to write off on your taxes—for example, job-search expenses, home-business costs, and medical expenses. (Hang on to these for seven years.) You may also want to keep receipts for pricey items, like electronics and appliances, in case you need to return them or make a warranty claim. Everything else is grist for the shredder.