Retirement is permanent. Many people think retirement means a permanent and abrupt exit from the workforce. But older workers are increasingly cutting back to part time, finding consulting work, or otherwise gradually transitioning into retirement. Some 45 percent of men and 41 percent of women born between 1933 and 1937 partially retired after age 50, up from a third of men and a quarter of women 20 years earlier, according to a recent Urban Institute analysis. And those who do exit the workforce completely don't always stay retired. More than a quarter of those born between 1933 to 1937 returned to work after fully or partially retiring, the Urban Institute found. "People don't want to continue to work full time, but they still need some income to supplement their retirement benefits," says Richard Johnson, a senior fellow at the Urban Institute. "I think we're going to see more people slowly phasing into retirement instead of making this dramatic change. Instead of going cold turkey into retirement they will step into it and get their feet wet."