Should You Plan On Your Retirement Lasting 30 Years Or 40?
The 4% rule has a planning horizon of thirty years. As I mentioned during the discussion of the PMT formula, different time horizons suggest different spending rates. An eighty-five-year old is not necessarily limited to a 4% spending rate.
Pfau, Wade D. PhD, "Should You Plan On Your Retirement Lasting 30 Years Or 40?" (2016). Faculty Publications. 581.