The authors considered an individual investor who holds a financial portfolio with funds in at least two of the following accounts: a taxable account, a tax-deferred account, and a tax-exempt account. They examined various strategies for withdrawing these funds in retirement. Conventional wisdom suggests that the investor should withdraw funds first from the taxable account, then from the tax-deferred account, and finally from the tax-exempt account. The authors provide the underlying intuition for more tax-efficient withdrawal strategies and demonstrate that these strategies can add more than three years to the portfolio’s longevity relative to the strategy suggested by the conventional wisdom.