Most beginner investing advice is about getting started. But once you're past that stage, the mistakes that cost you aren't obvious — they're subtle.

Here are 3 I see constantly:

1. Over-diversification disguised as safety.

You don't need 47 ETFs. After a certain point, you're just buying the entire market with extra fees. If your "diversified" portfolio mirrors the S&P anyway, you're paying for complexity you don't need.

2. Ignoring sector rotation timing.

The market moves in cycles. Holding the same sector allocation year-round means you're always overweight somewhere you shouldn't be. Most intermediate investors know this conceptually but never act on it.

3. Treating all gains equally.

A 10% gain on a high-conviction, well-researched position is not the same as a 10% gain on a random tip. One is repeatable. The other is luck. If you can't explain why something worked, you can't do it again.

I wrote The Investor's Edge Ebook to help intermediate investors fix exactly these kinds of blind spots — with actionable frameworks, not theory.

If any of these hit home, it might be worth checking out.