The Cost of Waiting, Revisited

The Investing Fundamentals track already showed how starting a decade earlier can roughly double an ending balance, thanks to compounding. For retirement specifically, this effect compounds (literally) over an even longer stretch — often 30 to 40 years — which means the cost of waiting even a few years to start saving seriously can be measured in tens of thousands of dollars by the time retirement actually arrives.

Consider two people who each eventually invest $300 a month at a 7% average annual return, but one starts at 25 and the other starts at 35 — the exact same 10-year gap used in the Investing Fundamentals example, just applied to a full retirement timeline.

Starts at 25, invests to 65 (40 years):  ends with roughly $720,000
Starts at 35, invests to 65 (30 years):  ends with roughly $340,000

Same monthly amount, same return — a 10-year head start
roughly doubles the final result.

For retirement specifically, the effect of starting even a few years earlier is measured over an especially long timeline, often ____ to 40 years.

This isn't about making anyone who started later feel behind — Level 8 of this track covers exactly how to catch up if that's your situation. It's about making the case, as concretely as possible, for starting today rather than waiting for a 'better' moment that compounding doesn't actually reward you for waiting for.

In the worked example, what is the main reason the person who started at 25 ends up with roughly double the amount of the person who started at 35?

Starting to save for retirement a few years later than planned makes almost no real difference to the final outcome.