Vacations are supposed to be about fun, not spreadsheets. But when money is involved, a little planning can make a huge difference. Why pay extra for a first-class seat on the flight to an all-inclusive resort, where you'll spend the next ten days relaxing anyway? Or why save a few dollars by skipping travel insurance, only to risk spending thousands if something goes wrong? Not every travel expense is worth the splurge. Here’s our guide.