A new study has found that U.S. workers forfeited $52.4 billion in time-off benefits in 2013 and took less vacation time than at any point in the past four decades. Oxford Economics for the U.S. Travel Association's Travel Effect Initiative conducted the study, which studies the impact of forgone vacation time. American workers turned their backs on a total of 169 million days of paid time off, in effect "providing free labor for their employers, at an average of $504 per employee," according to the study. Joe Robinson, a productivity and stress management trainer and coach, says the issue is driven by a number of factors. "One, workers are afraid to take their vacations in the layoff era," Robinson said. "It might mark them as less 'committed' than coworkers. "But it does them no good whatsoever. People who take more time off tend to get more raises and promotions." So maybe if you are deciding to not take those vacation days, take them. It's not doing you, or the economy any good to be working then!