I'm not one for complicated charting methods or long lists of dos and don'ts. As with the basics of buying, a selling strategy should be straightforward. But not even the simple "buy low, sell high" suffices in this brave new economy. After all, "buy high, sell higher" holds true, too. Yes, times have changed. With basic, boring blue-chips like Procter & Gamble ( PG) now the poster children for volatility, and value investing about as alive as Elvis, these days it's hard to know what to expect from a fund. Except perhaps triple-digit returns -- lately the norm for many funds. And when you don't get them, you bail, right? So it seems that figuring out when to say goodbye is a lot easier than it used to be. As with stocks, just dump those funds that don't top the charts. Well, it's not that simple. No hard-and-fast rules exist, but I have a few general guidelines for a sell strategy. Consider dumping your fund when: You're losing sleep over it. Ask yourself: Does this money belong in the market in the first place? These days, you're probably getting more shut-eye with your aggressive growth fund than with that supposedly safe and stable equity-income portfolio. Yep, seems there's tech, which keeps going up, and everything else, which doesn't. But just because you didn't get out of your fund before it turned south, doesn't mean you have to keep riding it until it turns around. There are good reasons to get out if you shouldn't have been in the market in the first place: If your time horizon is fewer than three years or if you need the dollars soon -- to finance a down payment or to pay for your college freshman's sophomore year -- your money should be in a safer place. As for your emergency fund -- you know, the money that will pay for those unexpected turns in life like the leaky roof or your broken transmission -- that doesn't belong anywhere near stock mutual funds. There's no reason your portfolio should have you up every night worrying. Get rid of the parts that leave you sorry and sleepless. But remember that some funds are hostages to their sectors, not necessarily to bad managers. Not so long ago, biotech funds were going bust. Just look at them now. The fund consistently underperforms its peers. Emphasis on the word peers. How do you know if your fund, which hasn't beaten the Nasdaq in three years, is a has-been or is just part of an asset class that is currently out of favor? By comparing oranges with oranges, you can usually find the bad apple. Check out our site to see where a fund ranks among the Lipper asset classes, or get the goods from Morningstar. Both fund rating companies show where a fund ranks for a wide variety of time periods. Bottom line: If a fund bumps along the bottom for too long, cut your losses. Of course, that raises the question, how long is too long? Some experts say one quarter -- others say five years. I don't dump a fund after one bad quarter or two or three. A lot of long-term winners have weathered bad years. I learned that lesson the hard way by getting out of Van Wagoner funds at the end of 1997 when they had a very rough couple of quarters. Now the most high-octane of the high-tech funds, they have more than come back. A smart manager doesn't turn dumb overnight, and if you do a good job buying a fund, you shouldn't have to sell it too soon. You can probably hold on to most funds for at least a year and a half to two years -- maybe even a little longer. Keep comparing returns on a quarterly and annual basis. During that time, look for your fund to move to the top quarter of its class. If it doesn't, then replace it. And while you're comparing performance, take a look at relative fees, too. It isn't always true, but sometimes poor performance and high fees go hand in hand. You should expect more -- not less -- from the funds with big price tags. Next week, more guidelines for selling your fund.