Compound interest and why time beats amount

Simple interest pays you only on the original amount you put in. Compound interest is different: each period, you earn returns on your original amount AND on all the returns you've already accumulated. Over time, this creates an accelerating snowball effect — the longer it runs, the faster it grows. Here's a concrete example. Suppose you invest $200 per month at an average annual return of 7%. After 10 years you've put in $24,000 — and your balance is roughly $34,600. The extra ~$10,600 is compound growth. Keep going to 30 years, and you've put in $72,000 total — but your balance reaches approximately $244,000. That's more than three times your contributions. The early-bird vs. late-bird comparison makes this even sharper. Person A invests $5,000 per year for only the first 10 years (years 1–10), then stops and lets the money grow untouched for 30 more years — a total of $50,000 invested. Person B waits, then invests $5,000 per year for 30 years (years 11–40) — a total of $150,000 invested. At 7%, Person A ends up with roughly $526,000 while Person B reaches only about $472,000. Person A contributed one-third as much money yet finished ahead, purely because their money had more time to compound. These numbers are illustrative, not forecasts — real returns vary. But the lesson is robust: time in the market is the single most powerful variable you control. Starting early, even with small amounts, gives compounding the runway it needs.