Who ever said that you had to work hard to become a millionaire?

Somewhere, someone came up with the idea that successful investing takes a lot of effort -- and it stuck. For those who enjoy managing their investments, there's no limit to the amount of time you can spend on research. Legendary investor Warren Buffett reads through hundreds of company annual reports each year. Just keeping up with regular news items on a portfolio of a couple of dozen stocks can be too much for some investors to handle. With thousands of public companies to choose from, you're never in danger of running out of prospects for further research.

Nevertheless, you don't have to be a stock jock to invest successfully. With mutual funds, all it takes to reach your financial goals is a regular investment program, time, and the discipline not to mess with a system that's working for your portfolio.

Buy-and-forget investing
In the latest issue of the Fool's Champion Funds newsletter, our resident mutual fund expert, Amanda Kish, talks about the potential pitfalls that come from constantly obsessing over your investments. When you're looking at stock and fund prices all the time, it's a lot harder to stick with the slow-but-steady method of making regular additions to your investment accounts. Instead, the short-term focus tempts you to try to time the market -- which can take you out of stocks at exactly the wrong time.

Rather than checking your stock quotes 50 times a day, the road to riches is a lot smoother if you put together a portfolio of dependable mutual funds and exchange-traded funds. Then, anytime you've got more money to invest, you can just add to your existing positions, using the opportunity to rebalance your investments if necessary.

What you should own
If the idea of kicking back with a mai tai in one hand and a good book in the other while your portfolio grows to a million or more sounds appealing, then the next step is to find the right group of investments. To put together a low-maintenance portfolio, here's what you should include:

  • A core set of funds that own large-cap stocks. Dependable blue-chip names like Microsoft (Nasdaq: MSFT) and Wal-Mart (NYSE: WMT) aren't likely to repeat the stellar returns from earlier in their histories. But high-quality large-cap funds can outperform the S&P 500 and give you a strong foundation for your investments.

  • Funds that invest in smaller companies. Large-cap stocks provide strong, steady returns over time. But because they're closely followed by Wall Street analysts, large-cap stocks usually aren't going to be where you earn the highest returns. So, pioneering small-cap funds that seek out the businesses that Wall Street overlooks -- companies like financial information provider Bankrate (Nasdaq: RATE) or specialty chemical maker Innophos (Nasdaq: IPHS) -- can boost your performance substantially.

  • A good international fund. Recent years have shown how important global diversification is for your investment performance. Between the falling dollar and the strength in emerging markets like China and Brazil, some of the best investment opportunities are outside U.S. borders, especially when the local economy isn't so hot. If you don't have exposure to companies like Asian online gaming company GigaMedia (Nasdaq: GIGM) or European steel giant ArcelorMittal (NYSE: MT), you're arbitrarily limiting your profit potential.

  • Funds to provide income. A combination of income-producing funds can help buffer your portfolio from big bumps over the years. Bonds have no real growth potential, while funds that invest in real estate investment trusts (REITs) like Vornado Realty (NYSE: VNO) provide both current income and possible price appreciation.

Time is on your side
Once you've put together a comprehensive portfolio, all that's left to do to become a millionaire is to let your money work for you. As you can see below, how long it will take depends on two things: how much you save, and what returns you get.

How long it takes to earn $1 million

Monthly Savings

8% Return

10% Return

12% Return


44.3 years

37.7 years

32.9 years


33.3 years

28.8 years

25.5 years


25.5 years

22.4 years

20.1 years


18.3 years

16.5 years

15 years

Getting to $1 million doesn't take huge amounts of savings or aggressive returns. Even modest investments over time will get you to your goals. Of course, the more you can save and the better your investments do, the faster you'll get there.

So if you've hesitated to start investing because you think it takes too much time and effort -- or if you're unhappy with your investment results so far and just want to make your life easier -- set up a buy-and-forget portfolio today. You'll be glad you did.

Want some help setting up a low-maintenance investment plan? The Motley Fool's Champion Funds newsletter recommends a number of different fund portfolios to match your preferences and needs. A free 30-day trial of the newsletter will let you see which funds we think will earn market-beating returns. Take a look for yourself and see how Champion Funds can make your life easier.

For more simple ways to make money, read about:

Fool contributor Dan Caplinger is on his way to a million bucks. He doesn't own shares of the companies mentioned in this article. Bankrate is a Rule Breakers recommendation, while Innophos is a Motley Fool Hidden Gems pick. Wal-Mart and Microsoft are Inside Value selections. GigaMedia is a Global Gains recommendation. The Fool's disclosure policy can help make you a millionaire.