It seems like we're all busier than ever these days, doesn't it? We've got a mere 24 hours a day, and in that modest allotment we're expected to find time to sleep, work, play, love, eat, raise children, shop, repair stuff, wash, grumble, celebrate, volunteer, grieve, exercise, pray, learn, travel, and more. Whew! No wonder we never seem to get everything done. And to the list of things we don't always get around to, we can add: invest our money effectively.

That's so much easier said than done, isn't it? Sure, if you have some discipline, you can be good about regularly depositing money into your brokerage account or a retirement plan. But that's not enough. You need to find good places for that money.

And finding the time to find these good places is not going to be easy. Just squeeze it in between your 9-to-5 job, your bowling league, your kids' judo lessons, the most recent episode of Law & Order, and your house that keeps getting dusty. Here's an idea: Hire another busy person to do most of the work for you. You might wish that instead of spending all your time at work, you could spend a few hours researching investments, but that's not realistic. There are some smart people out there, though, who spend all their time finding great investments -- and they can find them for you, if you buy in to their mutual funds.

Small differences, big differences
Once you decide you want to invest in mutual funds (as I've been doing more and more, myself), you have to decide which funds are right for you. There are, after all, about 8,000 of them out there! Here's one tip: When evaluating contenders, there are many factors to consider other than performance, though it is important to look closely at long-term performance.

For example, consider the Dodge & Cox Stock (FUND:DODGX) fund. It's lauded by many, and for good reason. Its 10-year average annual return is about 14.5%. Its top holdings, as of the end of 2005, included Hewlett-Packard (NYSE:HPQ), Sony (NYSE:SNE), and Comcast (NASDAQ:CMCSA). Now compare it with another highly rated fund, the Eaton Vance Large-Cap Value fund, with a 10-year average annual return of 12.15%. Its top holdings are General Electric (NYSE:GE), Bank of America (NYSE:BAC), and Citigroup (NYSE:C).

Both funds sport expense ratios (read: fees) on the low side, and both may look as though they'd do really well for you. But the small difference in those percentage points really matters. We can't know how these funds will fare in the years to come, but for illustrative purposes, let's see how $10,000 would grow over the next 40 years at 14.5% and 12.15%:

12.15% 14.5%
10 years $31,477 $38,731
20 years $99,080 $150,006
30 years $311,873 $580,985
40 years $981,683 $2.25 million

Did you see that? The difference, after 40 years, is more than a million dollars. And even after just 20 years, it's more than $50,000. (Remember that even 12.15% is a respectable return.) Both columns show how your money could be growing, on its own, with little effort from busy you.

I've now got some good news and some bad news for you. First, the bad: The Dodge & Cox fund is closed to new investors. Sorry. (This may be a good thing, actually. It has grown very big over the years, so it will be harder to keep up its impressive returns.) Now the good: There are plenty of other excellent mutual funds out there with solid long-term track records and attractive prospects. I'm talking about funds with managers whose philosophies you'll respect.

So when you're searching for funds (and managers) to give your hard-earned money to, keep it simple. Know that every percentage point -- every fraction of a percentage point -- matters, as the table above demonstrates. Pay attention to a fund's fees (relative to its peers' fees), because any premium will come out of your pocket in the long run. Make certain that the managers of the fund have a proven track record and that they are shareholder-friendly. (Fool fund guru Shannon Zimmerman generally requires that managers have held their post for at least five years.)

Let us help you
If you don't think you have the time, skills, or interest to find these funds on your own, let us help. Our MotleyFoolChampion Funds newsletter has many exceptional funds on its scorecard, and you can try it for free with a 30-day guest pass. Shannon's no slouch: His picks are up an average of 21%, versus 10% for similar amounts invested in the S&P 500 over the same time period.

You can also learn much more in these Zimmerman articles:

Here's to a happier portfolio! (Consider forwarding this article to anyone you care about. Just click on the "Email this page" link near the bottom of the page.)

Selena Maranjian 's favorite discussion boards include Book Club , Eclectic Library, Television Banter, and Card & Board Games. She owns shares of Comcast. For more about Selena, viewher bio and her profile. You might also be interested in these books she has written or co-written:The Motley Fool Money GuideandThe Motley Fool Investment Guide for Teens. The Motley Fool is Fools writing for Fools.