Time horizon vs. the retirement 4% rule
The planning horizon for the 4% rule is 30 years, but how long will your retirement really last? One of the key difficulties of planning a retirement income strategy is that this question is difficult to answer. We may know our life expectancy, but that is just an average and there is a great deal of variability around that average. To be conservative, one must definitely plan to live longer than their life expectancy.
Pfau, Wade, "Time horizon vs. the retirement 4% rule" (2013). Faculty Publications. 150.