Top 10 DIY Investor Mistakes (and how to avoid them)

About this episode

This episode discusses the top 10 mistakes DIY investors make and provides strategies to avoid them.

Most DIY investors don’t have an investing problem—they have a behavior problem, and this episode proves it with hard numbers: over the last 10 years, the average investor trailed the S&P 500 by about 3.3% per year, and even over 20 years they lagged by roughly 1.1% per year. We break down the 10 most common mistakes—from panic-selling and market timing to performance chasing, poor diversification, and treating investing like entertainment. Then we lay out an “advisor-like” improvement plan you can implement immediately: a one-page investing rulebook, automation, and a simple rebalancing system designed to keep emotions from hijacking results. We wrap with practical guidance for listeners who decide they want professional help, including what to look for in a fiduciary CFP® at a Registered Investment Advisor.

Topics covered

• DIY investing
• investor behavior
• investment mistakes
• financial planning

Keywords

• panic-selling
• market timing
• performance chasing
• poor diversification
• investing rulebook

Mentioned in this episode

Products: one-page investing rulebook, automation tools, rebalancing system

More episodes of Dollars & Common Sense

• Tax Planning vs. Tax Filing: Why It Matters · April 16, 2026 · 43 min
• Decisions You Make During the Year That Shape Your Taxes · March 26, 2026 · 43 min
• The Financial Advice People Wish They Had Followed 10 Years Earlier · March 12, 2026 · 43 min
• From Paycheck to Portfolio: Turning Savings Into Steady Income · February 26, 2026 · 43 min
• The Retirement Red Zone · February 12, 2026 · 43 min
• The 2026 Money Reset -- Actions to Win the Year · January 15, 2026 · 44 min