If someone offered you $1,000 today or $1,000 in exactly 10 years, the choice should be obvious — and not just because you might not trust them to still have the money in a decade. A dollar today can immediately be put to work: deposited, invested, or used to pay off debt that's charging interest. A dollar promised for later hasn't had that chance yet, and by the time it arrives, it likely won't buy as much anyway.
This is the time value of money, and it's usually expressed with a simple formula: FV = PV × (1 + r)^n, where PV is the present value, r is the rate of return, and n is the number of years. Invest $1,000 today at a 7% average annual return, and in 10 years it grows to roughly $1,967 — not because you added more money, but because each year's return starts earning its own return too.
Correct moves you up, wrong moves you down — reach 100 to master this lesson.