If you had just $50 to invest, would you put it toward your retirement or save it for your child's college education?

I know many parents would save first for college. It's natural. As parents, we often put our own needs last. Goodness knows I can't remember the last time I had a hot meal while eating with my young children.

If you've just sent your child off to college, you may be feeling like a martyr, having bypassed saving for retirement in order to give your child the best education you really can't afford.

But if that's what you're doing or plan to do, that's not a smart financial move. In this case, you have to put your retirement savings first.

Consider this. What advice does a flight attendant give a parent flying with a child? In the event of an emergency and your oxygen mask drops down, you're told to place the mask on yourself first before helping your child secure his or her own mask.

When I first flew as a new parent and heard this instruction, I internally said: "No sir. I'm going to take care of my baby first."

However, as the flight attendant pointed out, I needed to secure my mask first to be able to assist my child. Failing to do so could mean we both might pass out.

Fail to adequately save for your retirement, and your child (and his or her spouse, most likely) may pass out when you announce that you have to move in because you don't have enough money.

"The way many people think is they should get a house, then save for college, and then they think about retirement," said Duane Meek, senior vice president for retirement plans for Nationwide Financial Services Inc. "Retirement comes first and should be continuous. You really have other sources to finance your child's education. But when you get to retirement, if you haven't saved, you can't borrow that money because you can't pay it back."

Or you may have to work into your eighties because you can't afford to retire. In a recent survey, Fidelity Investments found that 55 percent of workers aged 25 and older said they anticipate having to push back their retirement timetable because they aren't saving enough. Thirty-five percent of the respondents said they will retire later than they would like because they started saving too late.

Adults aged 25 to 40 were more likely to cite the need to pay for a child's college education as a reason for hindering their plans to retire.

Here's an example from Meek that might change those parents' minds: Suppose you're a 30-year-old parent who began saving for retirement the year your child was born. Assume you retire at 67 and had a starting salary of $35,000, which increased 3 percent each year until retirement.

You could have saved more than $750,000 if you had invested about 6 percent of your salary in a 401(k) and received a 3 percent employer match with a modest annual return of 7 percent.

Conversely, Meek said, a person who began saving for retirement after sending a child to college would have saved only a little over $185,000 at retirement.

With the college year starting, Meek offers these tips on saving for your retirement and your child's college education:

* Apply for scholarships and financial aid even after your child's freshman year. According to the College Board, there are more than 2,300 sources of college funding, totaling nearly $3 billion in available aid. Take the time to do the research. Remember, your child can borrow to get an education.

* Encourage your child to contribute to his or her education by taking a part-time job. You don't have to do it all. Those school breaks could give you a financial break if you require your child to find work rather than hang around the house.

* Use student loans. With current interest rates on education loans of about 3.5 percent, a child's education can be financed with a low monthly payment.

* Take advantage of products that can help pay for your child's education without damaging your own financial future. For instance, a loan from your life insurance policy might help finance college expenses without risking your retirement savings because you might need less insurance protection as your college-age child gets closer to being able to live on his or her own.

* Make it automatic. It's easier to save money when you set up an automatic way to do it.

* Stop thinking it's all or nothing. If you only have $50 to invest, take some and put it away for your retirement and some for your child's college education. Remember, even small savings can grow to big dollars thanks to the power of compounding.

As you celebrate Labor Day, think of all your hard labor, both on your job and for your children. You deserve to retire when you want to. But that might mean taking care of your investment needs first. And that's okay.

* On the air: Michelle Singletary discusses personal finance Tuesdays on NPR's "Day to Day" program and online at www.npr.org.

* By mail: Readers can write to her at The Washington Post, 1150 15th St. NW, Washington, D.C. 20071.

* By e-mail: singletarym@washpost.com.

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