Once you retire, the order in which you draw down your savings is important. You want to maximize your income by using your least-taxed savings, first.

Begin by tapping any tax-free savings you have in a Roth IRA. Since you paid taxes on the contributions, you don't owe the government a dime on any withdrawals once you reach 59 1/2.

Then move on to taxable accounts not held in other types of retirement plans. Profits from stocks, bonds or mutual funds you've owned for more than a year are taxed at 15%.

After that, draw down tax-deferred retirement accounts, such as traditional IRAs or 401(k) plans. You'll owe taxes on withdrawals at your current income tax rate -- 15% or 25% for couples with taxable income between $15,650 and $128,500 this year.

One exception to the rule: When you reach 70 1/2 years old you must begin making minimum withdrawals from traditional IRAs and 401(k) plans or pay onerous penalties. So you've got to do that even if you haven't exhausted other, less taxable assets.