To ensure financial support in retirement years, young couples need to plan a withdrawal strategy that will last for 30 to 40 years. Let us assume a conservatively invested tax deferred retirement portfolio has an expected yield of about 8 percent. This corresponds to a retirement portfolio in an IRA or 401(k) plan invested in 60 percent conservative stocks and 40 percent intermediate-term U.S. Treasury Securities. For retirees who wish to maintain a consistent lifestyle throughout their retirement, they must decide on an initial amount to withdraw from their assets, and each year, increase that amount for inflation. If we could count on both the portfolio's actual annual return and inflation to be a constant 8 percent and 3 percent, respectively, then it would be relatively simple to decide on the initial amount to withdraw. If 5 percent is withdrawn for real return of the portfolio, then 3 percent would be left to increase in value for next year's inflation, thus the portfolio would never be depleted.