Between the two extremes of Jeff and Jack, there are realistic situations in which compound interest helps the average individual. One of the key concepts about compounding is this: The earlier you start, the better off you'll be. So what are you waiting for?
Let's consider the case of two other investors, Luke and Walt, who'd also like to become millionaires. Say Luke put $2,000 per year into the market between the ages of 24 and 30, that he earned a 12% aftertax return, and that he continued to earn 12% per year until he retired at age 65. Walt also put in $2,000 per year, earned the same return, but waited until he was 30 to start and continued to invest $2,000 per year until he retired at age 65. In the end, both would end up with about $1 million. However, Luke had to invest only $12,000 (i.e., $2,000 for six years), while Walt had to invest $72,000 ($2,000 for 36 years) or six times the amount that Walt invested, just for waiting only six years to start investing.
Clearly, investing early can be at least as important as the actual amount invested over a lifetime. Therefore, to truly benefit from the magic of compounding, it's important to start investing early. We can't stress this fact enough! After all, it's not just how much money you start with that counts, it's also how much time you allow that money to work for you.
In our first example, Jack had to save $25,000 a year for 40 years to reach $1 million without the benefit of compound interest. Luke and Walt, however, were each able to become millionaires by saving only $12,000 and $72,000, respectively, in relatively modest $2,000 increments. Luke and Walt earned $988,000 and $928,000, respectively, due to compound interest. Gains beget gains, which beget even larger gains. This is again the magic of compound interest.
Why Is Compound Interest Important to Stock Investing? >>