I moved to California in 1999 with a small stake from the 401(k) at my previous job. I made just about every investing mistake on the map trying to protect that stake from the whims of Wall Street. When I finally realized I was in over my head, I parked it all in a half-dozen Vanguard mutual funds a couple years ago and let the market do its work.

The first thing I did was the worst: I put all the money into one Vanguard growth fund at one price. Which meant that not only was I hostage to whatever pain the market might inflict on that single fund, I was also hostage to a single price. As long the fund was over the $34 purchase price I was fine, but here’s the rub: In the eight years since the original transaction this fund still trades under $34.

I sold off a bunch of the fund in around 2001 or so to preserve capital. About a year later I decide that ol’ “diversify your risks” thing might be a good idea, so I divvied it up among four stock funds (a small-cap, a mid-cap, a mixed fund and the original growth fund) and two bond funds. I bought all these funds at incredible bargains because of the bear market, whose gyrations over the next couple years got me thinking I ought to try my hand at trading individual stocks, during which time I promptly squandered these bargains.

Trading stocks instructed me in a few things: 1) broker commissions are killers; and 2) it’s not for the impatient or cowardly. All I ever did was lose money.

One thing I learned from reading the blogs of active traders is that you have to have a) a system (and the discipline to stick to it): and b) an edge: something combination of insight and skill that keeps you on the profitable side of trades. If you have neither system and nor edge, you might as well toss your dollars to the breeze.

I got fed up with trading just before the bull run of 2004 that lasted up until a couple months ago. Instead of just pouring all my money back into my mutual funds at a single price, I set up an automatic investment that put bought the same dollar amount of stock each month from each fund. They call this dollar-cost averaging, and the advantage of it is obvious at times like now, when the market’s going crazy again: I buy more shares when prices are low, and fewer shares when prices are high, and I’m losing money only on the most recent purchases; all the others, bought when prices were lower, are safe (for now anyway).

In retrospect, of course, I would have made tons more money if I’d just poured all my cash back into those stock funds three years ago, but the trouble with the financial markets is it’s like trying to drive your car via the rear-view mirror. You can’t see what’s coming; all you have are the hints provided by where you’ve been.

Something else I learned: The surest way to improve your fund balance is to keep adding money to it. This is why I’ll always park at least a chunk of money in my two bond funds: they pay cash money, which gets invested in more shares of the funds. The more shares I own, the more the funds pay.

Bottom line is I can ride out the current mess without inducing an aneurysm, because I know the market won’t hit all my funds with the same force, and most of the risk is lies in the small number of shares I bought at the most recent prices; the rest are essentially safe (in the short run anyway; a protracted bear market could bite me in the fanny again, I suppose.)

When I got into the market like everybody else during the 401(k) boom of the ’90s, I had no concept of dealing with the risks. When the crash happened I had no concept of protecting my assets.

Live and learn, as they say. This spring my original 401(k) balance finally got back to where it was in 1999, and the market promptly nose-dived again. But at least my money’s spread around so I don’t have to repeat my previous errors. The fun part will be learning from the next ones (which the market will gladly provide).