No matter how much you save or plan, sometimes there are unpredictable costs in life. Finances are hard, and some of the most expensive things in life are also the hardest to see coming. Unexpected medical costs can change your financial outlook overnight, whether from an accident or a diagnosis. A study by the National Bureau of Economic Research found that 19 percent of Americans would be unable to come up with $2,000 within 30 days if an emergency arose.