As college costs continue to soar, Americans who had been smart and fortunate enough to put aside money to cover college expenses have seen the value of that 529 Plan fall by $23.4 billion over the past year -- a decline of some 21%. This comes as college tuition prices rose another 5.6% over the last year, leaving families with a pretty big problem: less money to pay for something that is more expensive.

For precociously financially savvy families with young children, these declines aren't such a big deal -- annoying but there's enough time left that they don't have any immediate impact on college affordability. For families with high school students though, these declines can be a disaster -- especially when home equity is no longer available to tap into for college expenses, retirement portfolios are in the toilet, and that annual bonus isn't as good as it used to be.

The lesson to be learned from this beat-down is the same one that many retirees are learning as they watch 401(k)s and IRAs plunge: If you are investing money that you will need for a certain expense that will come up within five years, it's not a good idea to be invested in the stock market. Stocks have outperformed nearly all other asset classes over the long-term but in the short run, they can be extremely volatile.

So here's your homework: If you have a 529 Plan set up for one of your kids, and he's under 14 years old or so -- don't even look at the statements. Continue to live your life and save as much as you can because college costs are continuing to soar and don't waste time and energy checking the month to month performance of assets you can't control and don't need to rebound in value for quite some time.

If your child is already in high school, make sure that you are transitioning your 529 Plan assets into lower-risk classes like bonds, CDs and savings accounts -- or those wonderful low-risk hedge funds offered by Bernie Madoff.