Sixty-five is the traditional age of retirement. For those who have spent the majority of their waking hours at work over the previous four decades, this is an enormous transition. For some people—particularly those who have not cultivated interests or social relationships outside of work—retirement represents a significant loss, and there can be difficulties with emotional adjustment. For others, retirement offers the opportunity to explore new interests and old passions, spend more time with friends and family, and give back to the community through volunteer work or socially meaningful part-time work. The extent to which people plan out a new life structure in advance influences their adjustment to retirement. Of course, much also depends on the financial resources and physical health of the retired adult, which in turn depends on social policies regarding retirement financing and healthcare.

Across developed countries the average lifespan has lengthened considerably. Projections show that the proportion of the population that is above sixty-five and eighty-five will grow tremendously in the decades to come. For example, according to U.S. census data, in 1900 people aged sixty-five and older comprised four percent of the population while those aged eighty-five and over comprised only 0.1 percent of the population. By 2050, these rates are projected to be 20 percent and 4.8 percent, respectively. This raises concerns about the ability of governments or corporations to fund retirement pensions. Lessening that concern are the same factors that account for the increased lifespan in the first place.

The advances in medical technology, nutrition, and lifestyle that have increased longevity also increase the vigor and productivity of seniors, particularly the “young-old” in their sixties and early seventies. In fact, many people reenter the work force soon after retirement, in volunteer or part-time positions, if not full-time jobs.