"And why the hell should I listen to you, some random girl named Morgan Housel?"

A special thanks to the reader who emailed me this fine note (I'm male, by the way). They bring up a great point: There's a lot of information, and even more ill-informed opinions, sloshing around out there. Choose whom you take advice from wisely.

I remember this problem vividly when I first began learning about investing and economics. It was frustrating beyond belief to take someone at their word, only to later learn they were either certifiably clueless or fringe lunatics.

The best way to circumvent this is to pay special attention to advice given by those who are demonstrably successful at what they do. That's pretty obvious. And finding these teachers is fairly easy in investing: Annual returns provide a universal yardstick that objectively distinguishes the truly great from the merely good from the average from the bad.

So here are five bits of timeless advice given by five investors who have proven to be among the greats.

1. "A thoughtful investment process contemplates both probability and payoffs and carefully considers where the consensus -- as revealed by a price -- may be wrong."
-- Michael Mauboussin

Mauboussin is chief investment strategist at Legg Mason (NYSE: LM). Besides a highly regarded investment manger, he's a phenomenal writer. I've always loved this quote because it succinctly describes what markets do: They price the odds of different outcomes. Perceived certainties are rewarded with high prices, uncertainty is punished with low prices. That's it.

Yet individual investors too often focus on payoffs without regard to the probability of that payoff, or whether the consensus estimate of that probability is just wrong. You don't have to look far to find examples of this -- Microsoft (Nasdaq: MSFT) in 1999, Google (Nasdaq: GOOG) in 2007. In both cases, investors got most of the story right, as both companies grew revenue and earnings in subsequent years. Yet anyone who invested during these times was slaughtered simply because (a) the probability of either company continuing to grow at the rate they had was low, yet (b) the consensus valued this probability as nearly certain. It was a recipe for disaster.

2. "The wise ones bet heavily when the world offers them that opportunity. They bet big when they have the odds. And the rest of the time, they don't. It's just that simple."
-- Charlie Munger

Munger, of course, is Warren Buffett's famed compadre at Berkshire Hathaway (NYSE: BRK-A)(NYSE: BRK-B). This quote really sums up what separates good investors from the rest. More often than not, it's not what they buy, but when they buy it. In late 2008, smart investors bet heavily on corporate bonds, and they made a fortune. Right now, the masses are betting heavily on corporate bonds, and they'll almost certainly lose money. The former acted opportunistically, the latter like a lemming.

3."Based on my own personal experience -- both as an investor in recent years and an expert witness in years past -- rarely do more than three or four variables really count. Everything else is noise." 
-- Marty Whitman

Whitman runs the Third Avenue Value Fund, and is one of the grandfathers of value investing. A great example of the lesson this quote provides is how different investors analyzed housing during the boom years.

Wall Street financial houses used every bit of arcane hieroglyphic wizardry to validate the idea that housing was a good investment. Former Citigroup (NYSE: C) CEO Chuck Prince, for example, once cited the confidence in the "math and science" of finance as a reason the bank went downhill. Referring to the ratings of collateralized debt obligations made by companies like Moody's (NYSE: MCO), Alan Greenspan himself said, "I didn't understand it and I had access to a couple hundred Ph.Ds."

Yet one investor, hedge fund manager John Paulson, simplified his view and figured the whole thing out. As told in the book The Greatest Trade Ever, Paulson and his team noticed that real estate prices were growing faster than household income, which was really all they needed to know to label housing as a bubble. And they were dead right -- Paulson made $20 billion betting the bubble would burst.

4. "The market does not beat them. They beat themselves, because though they have brains they cannot sit tight." 
-- Jesse Livermore

We can argue whether Livermore was really a successful investor. He made several investing fortunes, but died of a self-inflicted gunshot wound after losing it all for the umpteenth time.

Yet Livermore really only lost money when he broke his own cardinal rules and followed the crowd, which makes the above quote all the more compelling. Many investors can tell you word for word how to spot cheap stocks, when to buy them, and well to sell them. Yet very few actually act on it, or often do so at exactly the wrong time. In some ways, Livermore was one of them. Having knowledge and utilizing knowledge are two very different things.

5. "The four most expensive words in the English language are, 'This time it's different.'" 
-- Sir John Templeton

It never is. In the past century, we've gone from horse and buggy to iPhones. Yet markets are still prone to bubbles, booms still lead to busts, expensive stocks still return less than cheap ones, and people still do stupid things. It will always be that way.

Got any favorite quotes of your own? Feel free to share 'em in the comments section below.

Check back every Tuesday and Friday for Morgan Housel's columns on finance and economics.

Fool contributor Morgan Housel owns shares of Berkshire Hathaway. Berkshire Hathaway, Moody's, and Microsoft are Motley Fool Inside Value picks. Google is a Motley Fool Rule Breakers recommendation. Berkshire Hathaway and Moody's are Motley Fool Stock Advisor selections. Motley Fool Options has recommended a write puts position on Moody's and a diagonal call position on Microsoft. The Fool owns shares of Berkshire Hathaway and Legg Mason and has a disclosure policy.