Longevity — How Long is Retirement?
No healthy person can answer this question. So we must plan income for as long as we might live.
Well, how long is that? It could be pretty long.
Let's say you are 62 years of age and you have a spouse of the same age. If a married couple is in good health at age 62, there's a 50% probability that one of them will live to age 92. Do you remember what you were doing 30 years ago? Consider that one of this couple has a 50% chance of looking back to today, 30 years from now.
Plan Based on Potential Life Span
Chance of a 62-Year-Old Living to Select Ages

Of course, you should take into account your medical condition, your likelihood of a long life, and your desire for financial independence throughout retirement. Every retiree will have to make their own judgment on how long their retirement income should last. Remember, however, to factor in the impact of continued medical advances.
