A: Well, but what if it doesn't keep rising? You're right to think of the long run, but you also need to consider a company's intrinsic value.

Imagine Dodgeball Supply Co. (ticker: WHAPP), trading at a fair price of $10 per share. If it's expected to grow at 12 percent per year for the next 10 years, it should trade around $31 per share in a decade.

If you buy it at $10 per share, your total gain over the decade will be 210 percent. However, if you have to pay $15 per share for it now, it will return only a total of 107 percent on its way to $31. That's about 7.6 percent per year. Worse still would be buying it at $20 per share. Sure, you'd make money, but your total gain would be just 55 percent, or roughly 4.5 percent annually. Making matters worse, WHAPP might not live up to its expectations. When you buy at steep prices, you have less of a margin of safety.

Learn to value stocks with books such as The Little Book That Beats the Market by Joel Greenblatt or The Little Book of Value Investing by Christopher Browne (both from Wiley, $20).

Q: How can I find out ahead of time when various companies' earnings reports are due? - C.S., Winona, Minn.

A: You can always call the company itself. (Ask for the investor relations department.) If you're online, click over to http://biz.yahoo.com/research/ earncal/today.html, type in the firm's ticker symbol, and presto - earnings date info.

Fool's School: Big Can Be Bothersome

Most managed-stock mutual funds have underperformed the market, as measured by the Standard & Poor's 500, an index that tracks 500 of America's leading companies. The problem is partly size.

Imagine running a $40 billion mutual fund. That might sound exciting, but it's difficult. You might keep 5 percent or so of the fund's value in cash, to cover people's withdrawals. Those dollars won't grow much. With what's left, you probably won't be permitted to invest more than 5 percent of the fund's value in any one stock. So you'll have to own at least 20 stocks. (Mutual funds typically invest in 50 to 200 companies.)

To appreciate this over-diversification, consider Fidelity's mammoth Contrafund, valued at more than $75 billion. As of the end of 2007, its biggest holding was Google, representing 5.4 percent of the fund's value. If an investor had plunked $3,000 into Contrafund then, he or she would own only $162 worth of Google, less than a single share. A grand total of $114 would be divided among 13 pharmaceutical companies (such as Merck and Schering-Plough). When you're invested in hundreds of companies, if some of them do very well, their impact is diluted by many less-stellar performances.

Even if you wanted to (and could) spend 10 percent of your $40 billion fund's value, $4 billion, on one company, you may run into problems. As you bought many shares, you'd drive the stock price up. Also, let's say you think Cheesecake Factory would be a great investment. Oops. Its entire market value is just about $1 billion. You can't buy entire companies. If you're limited, as many managers are, to not buying more than 10 percent of any one company, you can spend only about $100 million on it. It's hard to avoid spreading yourself too thin when $100 million is merely a drop in your mutual fund's bucket.

For most investors, index funds are the best solution. Learn more at www.fool.com/mutualfunds/mutualfunds.htm and www.indexfunds.com.

Foolish Trivia

Born in 1971 and based in Ohio, not St. Louis, I'm an $87 billion global manufacturer and distributor of medical and surgical supplies and technologies. I serve hospitals, medical centers, retail and mail-order pharmacies, clinics, physicians, and pharmacists, among others. I make more than 50,000 deliveries to 40,000 customer sites daily. I make more than four million medical and surgical products that are used in 50 percent of all surgeries and 90 percent of all hospitals in America. I make Alaris, for example, a top intravenous infusion system. I'm ranked No. 19 in the Fortune 500. Who am I?

Last Week's Trivia Answer: I was founded in Yonkers, N.Y., in 1853 by a guy who invented a safety mechanism for a lifting platform. I installed the elevators in the Eiffel Tower, the Empire State Building, and Manhattan's World Trade Center. I began installing elevators in China in 1907. Today I'm the world's biggest maker, installer and servicer of elevators, with more than 135,000 elevators and escalators sold each year. More than two million of my machines are operating worldwide. United Technologies bought me in 1976. I rake in nearly $12 billion annually, mostly from outside the United States. Who am I? (Answer: Otis Elevator Co.)

Perk up your ears, snow bunnies. "Motley Fool Hidden Gems" recommendation Vail Resorts (NYSE: MTN) has come to own some of the choicest ski resorts in the United States, including Vail, Beaver Creek, Breckenridge and Keystone.

These ownership positions provide Vail with a very impressive economic moat. The company also complements its ski resorts with the development and management of hotels, resorts and private residences, making Vail's quarterly fluctuations less of a concern.

Vail's third-quarter results featured total sales up almost 15 percent, but earnings below expectations. Still, that's somewhat understandable given that food and energy inflation leave fewer discretionary dollars for consumers to spend on ski vacations.

CEO Robert Katz proclaimed his excitement for strong ski-pass sales results and the introduction of the Epic Season Pass to allow "skiing at all five of our resorts for the entire season." There are also real-estate developments in the works, as Vail looks to diversify from its winter-destination heritage.

After a recent slide, Vail's stock could be had for less than 20 times this year's earnings projections. That's not yet a steal, given the more challenging economic climate right now, but keep an eye out for a further pullback, as Vail Resorts offers a unique collection of properties for the vacation-minded. Perhaps add the company to your watch list.