Everyone has to start somewhere, even the wealthiest, most successful people.
Billionaire Warren Buffett hasn't always been as incredibly rich as he is today. In fact, 99% of his wealth was earned after his 50th birthday.
The investing legend has been slowly building his fortune over the years, and today, the 85-year-old billionaire is one of the richest men in the world, with an estimated net worth of over $60 billion.
How did he come to earn such a mind-blowing amount of money?
Tony Robbins, motivational speaker and author of "Money: Master the Game," decided to ask him.
"And he smiled at me and said, 'Three things: Living in America for the great opportunities, having good genes so I lived a long time, and compound interest.'"
Buffett has always been an advocate of keeping things simple and focusing on the long term -; that's why he recommends low-cost index funds.
One of the keys to Buffett's wealth is simply time: 60-plus years of smart investing has allowed him to reap the benefits of compound interest.
Compound interest is when the interest earned on your investments earns interest itself. It's what causes wealth to rapidly snowball, and in Buffett's case, snowball to billions of dollars.