Asset allocation is as much art as science.

"There is no perfect portfolio," says Larry Swedroe, author of "Wise Investing Made Simple." "There's only that perfect portfolio based on your ability, willingness and need."

So how do you find a good match for your life right now? One smart solution: Meet with a financial adviser to examine your goals, risk tolerance, timeline and financial situation.

Then examine the ways different combinations of stocks and bonds will affect your portfolio for the long haul, says Peggy Cabaniss, CFP, president of HC Financial Advisors in Lafayette, Calif., and past chairman of the national board of the National Association of Personal Financial Planners.

"What is the perfect combo to help you reach your financial goals?" she asks.

Remember that one plan doesn't last a lifetime. You have to make alterations as your life changes. Your asset mix when you're in your 20s and just starting out in your career and life should look a lot different than the asset mix of your grandparents, who are in their 70s, retired and playing canasta.

To help you make those alterations, we have created four different portfolios, each designed to meet the needs of individuals at different stages of their lives. See which best describes your situation to get an idea of what might work best for you.

Portfolios:

• Young single The investor is a young grad, recently out of college with his/her first "real" job. The goal: saving for retirement. • Couple The investors are a young married couple with a child. Their goal: saving for retirement. • Middle-aged The investors are a middle-aged married couple with several children. Their goal: a comfortable retirement. • Seniors The investors are senior citizens who have recently retired. Their goals: hanging onto their money and earning enough return to make it last throughout a long and healthy retirement.