T. Rowe Price Rule of Thumb

Based on computer models that ran thousands of market scenarios, the probability of a portfolio lasting 30 years if a retiree pursued the strategy of withdrawing 4% the first year, with a 3% increase each following year to account for inflation has an 89% chance of success assuming that the portfolio was invested in 55% stocks and 45% bonds ... however, the odds of lasting 30 years declined if average annualized returns were lower than 5% during the first five years of retirement ... for instance, the odds of success dropped to 64% if returns were between 2% and 3%.