Why the 4% Retirement Rule Should Become 5%

For nearly three decades, one of the most widely cited guidelines in retirement planning has been the "4 percent rule." Originally devised in the mid-1990s by financial adviser Bill Bengen, the rule suggested retirees could safely withdraw 4 percent of their portfolio in the first year of retirement and then continue withdrawing the same amount, adjusted for inflation, each year after.

The appeal was its simplicity: in year one, take 4.15 percent of your savings, then repeat with adjustments. The strategy was stress-tested against historical market downturns and became a reliable benchmark for retirees looking to stretch savings across three decades .

Now, Bengen has revisited his calculations. In his new book, A Richer Retirement: Supercharging the 4 Percent Rule to Spend More and En