Thing One The Most Valuable Thing You Can Put Into An Investment Is Time I came across an example recently that does a good job explaining compound growth. Imagine two people who both invest $3,000 a year and retire at age 70. The first starts at 22, invests $3,000 a year for 15 years, and then stops completely at 37. His total lifetime contribution: 15 years × $3,000 = $45,000. The second does nothing for those first 15 years. He starts at 37 and invests $3,000