Also posted this on the MI board.

Meet Joe Investor. Ten years ago, he was 48 years old, and had way more hair than he does today. But he'd been living below his means, and his retirement account had $600K worth of VOO (the Vanguard S&P 500 Index ETF). He was also able to keep saving $800/mo from his paycheck, and have that invested entirely in that same index ETF in his 401K every month. Yes, that's every month. Rain or shine. Pandemic or no pandemic. No market timing.

Let's say that Joe decided that his financial freedom/early retirement number was $2 million. How much would he have in his 401K today?

To answer that question, we just need to go to this excellent S&P 500 DCA calculator, plug in the start and end dates, the initial amount, and the monthly adds.

ofdollarsanddata.com - Dca calculator

Using August 2014 as the start month, we find that Joe's 401K has grown to $2,193,422. He can now cash out, go to a 60/40 allocation and retire early and happily at age 58.

Did Joe need the IQ of a genius to do this? Nope. He was just an average student in college. In fact, just by implementing this no-brainer strategy, Joe beat out the majority of money managers at mutual funds who DO have graduate degrees in finance from Harvard, Wharton, etc., and who spend their careers studying reports from Wall Street analysts who ALSO have MBAs from the top Ivy Leagues.

Mechinv
For success in investing, your emotional fortitude counts for way more than your intellect.