For those who have been trading US stocks for three years, here is a test:

Open your brokerage app, check your total return rate, and then look up how much the S&P 500 has risen during the same period.

I dare say 80% of people wouldn't dare to make this comparison.

Because the answer is likely: You spent thousands of hours researching individual stocks, waking up in the middle of the night to watch the market, chasing news in groups, and losing sleep from anxiety over earnings reports, yet your final returns are worse than someone who opened an account and basically never looked at it again.

That person only did one thing: dollar-cost averaged into the S&P 500.

If you don't believe it, open your app and calculate it right now.