The IRS mandates withdrawals from pre-tax retirement accounts once you reach a certain age. These are referred to as required minimum distributions (RMDs). For many retirees, RMDs don't change much since they already take out more than the minimum to cover living costs. But, for those who want to withdraw less than the required amount or leave money invested, RMDs can pose a challenge. To help you calculate how much to withdraw from your own retirement accounts, let’s walk through an example of a 78-year-o ...