It's tough enough to figure out how much money you need to have stashed away in order to retire. As you reach retirement age, the big worry is how much you can spend every year and still make your money last as long as you do! Now Fidelity Investments is launching two new products to help boomers do the double job of investing -- and withdrawing -- their retirement funds with a greater degree of confidence.A new series of "Income Replacement Mutual Funds" are each designed to self-liquidate, creating a stream of flexible payments that distribute both principal and growth to provide for retirement income. The funds offer the opportunity for growth and the flexibility of adding additional cash, or making additional withdrawals, all without penalty. At the target date of maturity, both income and principal will be totally withdrawn. But the mutual funds don't promise a check a month for life, or a death benefit, such as you'd find with traditional annuities. So at the same time, investors might want to consider Fidelity's new Guaranteed Withdrawal Benefit Annuity, its version of an increasingly popular type of annuity that offers a protected, lifetime monthly check that can grow based on investment returns. This product offers a lifetime payout promise, upside protection from inflation not found in traditional immediate annuities and a death benefit to survivors. But it costs more and is less flexible.