Buffett's long-time partner Charlie Munger, vice chairman of Berkshire Hathaway, passed away on Tuesday local time at the age of 99, just one month away from his 100th birthday.

Munger is a successful investor, and according to Forbes estimates his net worth is $2.6 billion. At the same time, he is also known for providing some practical life advice on a regular basis.

In 2019, Munger shared some of the secrets behind his optimistic attitude towards life in an interview, “All of these simple rules can make your life better. Even though they're so cliché,” Munger said.

Here are Munger's 6 tips for a happy life and a long life:

1. Don't be too jealous.

Munger has been warning of the danger of jealousy for decades.

In 1986, in a speech to graduates at Harvard University, Munger stated that jealousy “along with chemicals, creates pain to win a certain price in quantity.”

“The world is not driven by greed, but by jealousy,” Munger stated at the 2022 annual meeting of “The Daily Journal” where Munger is the director.

2. Never harbor resentment

In his 1986 speech at Harvard University, Munger also warned graduates not to harbor resentment. “If you want pain, I can't recommend it too strongly to you,” he said.

Munger has also suffered in her own life, including divorce, partial blindness, and the death of a son. Despite this, he tried to avoid resentment.

3. Measure input into output and stay away from harmful people

At the Berkshire Hathaway Shareholders' Meeting in May of this year, Munger gave some wise financial advice.

He said, “It's very simple. Measure what you get and invest wisely.”

He also pointed out that it is important to stay away from harmful people and harmful activities, live and learn until old age, and postpone immediate pleasure. “If you do all of these things, you'll almost certainly succeed. If you don't do that, you're going to need a lot of luck,” he said.

4. Stay optimistic in the face of adversity

Munger said in an interview in 2019 that “staying optimistic” is “a wise thing to do.” To stay happy, he said, the key is to release negative emotions.

“Can you still be happy when you are completely engulfed in deep hate and resentment? Of course you can't. Then why are you carrying them?” Munger said.

5. Dealing with reliable people

Munger attributes part of his success to being close to reliable people and avoiding toxic people.

One of the most reliable people in Munger's life was, of course, Warren Buffett. In 1959, the two met in their shared hometown of Omaha and formed a friendship that spanned over 60 years.

In his 2014 annual letter to shareholders, Buffett recalled, “Introducing the predictions of the doctors we know from Omaha, we would hit it off — and so it is.”

6. Do what you have to do

Munger also said, “Every day when you wake up, you should try to be smarter than before,” and “the best thing one can do is help another person know more.”

One last tip: eat a little candy

Munger also once said an unusual secret to longevity: eat a little candy, although this may be a joke.

In an interview in February of this year, Munger chewed peanut candy produced by See's Candy (See's Candy), a subsidiary of Buffett, and said it was the key to longevity.

“I'm eating this delicious peanut candy,” he said. “If you want to live to be 99, you have to do it.”