You know what's interesting about looking back at 2023? The market absolutely crushed it with that 25%+ return on the S&P 500, but here's the thing that caught my attention - this wasn't some once-in-a-lifetime event. Since 1926, we've seen market returns at this level happen 27 different times. That's more than once every four years on average. So yeah, 2023 was fantastic, but it wasn't exactly unprecedented.

What really got me thinking was the pattern before those big years. Most people assume that after a massive year like that, the market has to cool down. But the data tells a different story. Out of those 27 years with 25%+ returns, 16 of them were actually preceded by positive years too. That's kind of wild when you think about it. The narrative everyone pushes about mean reversion doesn't always play out.

Now, if you dig into what happened after those 25%+ return years, the average follow-up return was around 10.2%. That's still pretty solid. Though I'll be honest, the range is all over the place - you had 1927 with 44% gains and then 1936 with a 35% decline. Total chaos depending on the year.

Here's what I think matters for people actually dealing with their portfolios: if you don't need the money for at least a few years, staying invested makes sense. Even after incredible years, the historical trend is still up. The tricky part is if you've got something specific coming up - a big purchase, retirement, whatever - then you need to plan accordingly. But going all-in on cash is probably the wrong move because you'll miss out on the long-term growth.

For anyone who hasn't started investing yet, the timing argument is kind of overblown. Yeah, people always find reasons not to invest - overvaluation, political stuff, global instability - but these concerns have existed for nearly a century while the market still climbed. Index funds tracking the market returns have been the boring but reliable play throughout that entire period.

Looking back now at how 2023 played out and what followed, it's a good reminder that you can't really time the market. The best move is usually just staying the course.