Investment costs might not seem like a big deal, but they add up, compounding along with your investment returns. In other words, you don't just lose the tiny amount of fees you pay—you also lose all the growth that money might have had for years into the future.

Imagine you have $100,000 invested. If the account earned 6% a year for the next 25 years and had no costs or fees, you'd end up with about $430,000.

If, on the other hand, you paid 2% a year in costs, after 25 years you'd only have about $260,000.

That's right: The 2% you paid every year would wipe out almost 40% of your final account value. 2% doesn't sound so small anymore, does it?