Retirement is a very big decision because it is irreversible. Leaving your primary source of income, a job that you may have held for years or decades, to do things and spend time in ways you really enjoy can be exhilarating. If your resources are ample to support your living standard, life is a joy. If your resources turn out to be insufficient, however, you must either cut back on your living standard or attempt to increase your resources by going back to work. And it’s very unlikely that you’ll be able to just slide back into your old job, the one you left one or two or five or even ten years ago. A comprehensive plan is essential to assess whether the nest egg you’ve accumulated will support your living standard once you retire, even in the face of potential difficulties, such as unanticipated health care costs or poor portfolio performance.