Excerpt: The larger you plan to live, the more income you'll need, and the more you'll have to save. Granted, this won't give you an accurate-to-the-tenth-decimal-point figure. But you should be able to come up with a percentage that in your judgment is reasonable. You can then plug this figure into our Retirement Planner or a similar calculator and get a sense of what you need to do to hit that target.  MORE >>