What is a fashionista’s worst nightmare? Wearing something that’s was last season trend.

Today’s fashion trends – or fads – are very fickle. The fashion industry is constantly on the lookout for what’s new, what’s in, what’s hot. Must-have items do not stay that way for long.

The fashion cycle

The fashion cycle revolves quickly. The cycle begins with the arrival of the emerging trend. The American Marketing Association (AMA) calls this the "distinctiveness" part of the cycle. The new trend is very much sought after. You’ll know the trend has arrived when the look/item you saw is on the runway, the red carpet or a music video.

The next phase is when everybody wants a piece of the trend. The AMA calls this the emulation phase. The trend is splashed across fashion magazines, newspapers, internet, TV, etc.

The cycle ends when the market gets saturated by the trend. The prices go down and (former) must-have items become widely available as a knock-off.

Most people will buy it during phases 2 and/or 3. Only the privileged few can get it fresh off the runway. Most consumers won’t have access to the trend until it reaches the 3^rd phase.

About 20-30 years ago, it may have taken a few years for trends to get from runway to mass markets. Today however, the fashion cycle revolves overtime. Trends can go from red carpet to mass market in a matter of months.

Hot or Not

Affordable yet trendy looks work two ways. It grants people on a budget access to fashionable clothes. But this accessibility actually helps the trend saturate the market. In short, it helps kill the trend faster.

How long will a trend last?

Trends generally stay put for about a year. Some trends, which about.com calls "the most understandable ones", last much longer.

Some experts say that fashion cycles occur about every 20 years. Remember the bellbottoms? They resurrected as flared pants. Your 80s’ minis are currently making the rounds again.

When determining how long a trend is "trendy", think where in the fashion cycle did you buy the trend. If you bought it as a knock-off, then expect it to be "in" for two season’s tops. Remember, the fashion calendar group seasons together – Springs-Summer, Fall-Winter – which means you have approximately six months of wear before the trend looks dated.

Though there are no etched-in-stone guidelines in fashion, it’s a always a safe bet that the hard-to-pull off looks are just fads that will fade fast.

Remember, buying power can make a trend last longer. Consumers can grow so fond of a trend that they refuse to let it die. Capris, crops, tank tops and flip flops are good examples of trends that became wardrobe staples.

High-profile trends are more likely to look dated by next year. Likewise, trends that sport more radical prints, cuts and colors tend to live for less than a year.

Your best defense against the ever-changing fashion tides is to stock your closet with fashion staples and classic looks. Jeans, little black dresses, etc. Use trendy items to upgrade your classic get-up a "now" feel.