You've probably heard this axiom before: "The definition of insanity is doing the same thing over and over again and expecting a different result."

Such a sage principle of life is especially true when it comes to investing. Stock and bond markets are places where millions of different traders meet each day to agree on a price that both buyers and sellers can find acceptable — i.e., fair.

"No single trader can know more than or have a consistent advantage over the millions of other market participants around the world," noted Mark Hebner in his book "Index Funds: The 12-Step Recovery Program for Active Investors." He added: "Markets are likely to reward long-term investors, not short-term speculators." ¹

The IFA Founder and CEO characterizes those who think they can consistently beat such odds as "time pickers." Hebner wrote:

"Time pickers or market timers claim the ability to predict the future movement of the stock market, moving into the market before it goes up and getting out before it goes down. However, numerous studies from industry and academic experts demonstrate market times have no such ability to beat the market, and they should be avoided just like the lion's cage at (P.T.) Barnum's circus." ²

How harmful can mistiming markets be to your portfolio? Below is a chart we've created to illustrate what missing just a few of the market's best days can mean to performance over time. This look at a hypothetical investment in the stocks that comprise the IFA SP 500 Index shows that remaining invested helps to ensure that your portfolio is poised to capture what the market has to offer. Key takeaways from such research included:

• A hypothetical $1,000 turned into $6,347 from 2004 through 2023.
• The return dwindled to $2,910 if you missed the blue-chip index's 10 best days.
• Missing the best 20 days resulted in your return dropping to $1,750.
• Staying invested throughout this period would've returned an annualized 9.68%.