What The Heck is Compounded Interest?

Have you ever seen this story about the power of compound interest?

Like an example they use is the guy who saves $10,000 in his twenties and then allows it to accrue interest over 20 years or 30 years without ever adding more versus the guy who starts late.

He doesn’t start saving until his thirties or forties, or I can’t remember the exact details, but the gist of it is…