Do you run out of money with the 4% rule?

It states that you can comfortably withdraw 4% of your savings in your first year of retirement and adjust that amount to account for inflation for each subsequent year without risking running out of money for at least 30 years. So how do you know how long your money will last in retirement? Bengen found that retirees could safely spend about 4% of their retirement savings during the first year of retirement. If you rely on a fixed 4% in good times and bad times, things may or may not work out, but you're taking a risk by employing a rigid approach to retirement planning.