Warren Buffett credits much of his success to having a great business partner. He has worked with Charlie Munger for 45 years. They've been friends for even longer than that. 

Many investors have benefited from listening to Buffett's wisdom through the years, but there's a lot to learn from Munger, too. In Buffett's latest letter to Berkshire Hathaway (BRK.A -2.04%) (BRK.B -1.96%) shareholders, he noted that he and Munger usually think alike. However, Buffett maintained that his partner's thoughts are "always more clearly reasoned and also more artfully -- some might add bluntly -- stated."

In his letter, Berkshire shared several quotes from Munger. Here are seven timeless investing lessons from Buffett's longtime business partner. 

A person wearing glasses looking up at drawings of light bulbs with one bulb containing a dollar sign.

Image source: Getty Images.

1. "The world is full of foolish gamblers, and they will not do as well as the patient investor."

Some people view investing as gambling. Munger astutely dispelled this idea in this statement. Some people buy stocks with a gambler's mentality, but they typically won't perform nearly as well as a person who invests in a business, holds onto the stock, and gives that business ample time to grow.

2. "If you don't see the world the way it is, it's like judging something through a distorted lens."

It's easy for investors to rely on wishful thinking instead of careful analysis. If you follow Munger's advice, though, you'll try to recognize the biases you have and push them aside. A company's actual business prospects are what's important, not what you hope those prospects will be.

3. "Don't bail away in a sinking boat if you can swim to one that is seaworthy."

Don't think that buy-and-hold investing means you never sell a stock. Buffett and Munger won't hesitate to sell a company's stock if they don't believe the business is solid. If the premise you had for buying a stock ceases to be valid, consider selling it and reinvesting in a better opportunity.

4. "Warren and I don't focus on the froth of the market. We seek out good long-term investments and stubbornly hold them for a long time."

Smart investors will follow the examples of Buffett and Munger, and avoid getting caught up in "the froth of the market." Focus instead on the businesses you've invested in. Munger's statement here is reminiscent of something Buffett wrote years ago to Berkshire shareholders: "Our favorite holding period is forever." He has a prerequisite for stocks he's going to hold for the long term, however: The underlying businesses and their management teams must be "outstanding." 

5. "There is no such thing as a 100% sure thing when investing. Thus, the use of leverage is dangerous." 

Investing inherently comes with risks, and you should know the extent of the risk you take on with any investment. As Munger warned, using leverage (borrowing money to invest more heavily) can increase your risks significantly.

6. "You don't need to own a lot of things in order to get rich."

This statement parallels something that Buffett wrote in his recent letter to Berkshire shareholders: "Our satisfactory results have been the product of about a dozen truly good decisions." Buffett also revealed his "secret sauce" for achieving success in investing: "The weeds wither away in significance as the flowers bloom." The "weeds" are poor-performing stocks and the "flowers" are stocks that deliver tremendous gains. Buffett noted, "Over time, it takes just a few winners to work wonders."

7. "You have to keep learning if you want to become a great investor. When the world changes, you must change."

Munger is 99 years old. Buffett is 92. The world is far different now than it was when they first began investing. Their ability to be successful for so long is largely the result of their willingness to continue learning and adapting.

Bonus: One investing tip from Buffett

Buffett included several other quotes from Munger in his latest letter to Berkshire shareholders in addition to the seven listed above. He also added a tip of his own: "Find a very smart high-grade partner -- preferably slightly older than you -- and then listen very carefully to what he says." Buffett has taken that advice to heart with his relationship with Munger -- and it's made him wealthier through the years.