Most investing advice assumes you invest in an index fund on Jan 1 and hold for 30 years, then quotes an average annual return.

But that’s not how many people actually behave. You open a brokerage account on some random day, invest what you have, and you might care a lot about the value in, say, 5–10 years (buying a house, etc.).

I tried a simple experiment: pick a random day, invest in the index, hold for n years, and look at the distribution of outcomes.

Write-up (with methodology and charts) here: https://quantitativecuriosity.substack.com/p/stock-market-in...

I’m curious how others here think about risk/time horizons for “normal” investors who don’t cleanly fit the textbook 30-year model.