Studies show that people in the United States are waiting longer to retire. Whether it’s because they’re motivated to stay active in a career, want to make a difference in the world or struggling with skyrocketing bills, 46 percent of US employees over 50 now say they plan to work longer than they once expected. A third of workers 55 to 64 expect to work at least five years more than originally planned, according to a 2011 Towers Watson survey.