In your lifetime there will be lots of trends that come and go. Some you hate when you first see them, but they grow on you. Some you love even though they are bizarre or unflattering. Some trends you may just never understand. Even though it is against the whole concept of fashionable behavior I believe it is always important to stay true to yourself no matter what is trendy. Sometimes it is hard to tell if you like something because YOU like it or because you have seen a million people wearing it and you have just gotten used to that look.
Fashion is planned obsolescence at it's peak, Items made to only last a season. The only thing I can think of that even comes close is electronics. Fortunately some items are cyclical as well and if you take good care of your clothing everything will come back in to style eventually.
There are things that are very trendy right now that I can not stand. Not to offend anyone, like I said, this is about being true to yourself so I am certainly not trying to bash anyone Else's style. I hate Ugg boots. I have since they started showing up several years ago. I also hate leggings. I have a few pairs because they are comfortable to wear under roller derby shorts during the winter, and as a mother comfort in general has a new found place in my heart. (and my poor heels are getting dusty-and obsolete ;) in the closet). I don't like most of the 80's resurgence and I LOVE that this spring is all about underwear as outer wear (and yes, I am aware that that actually started in the 80's before Stella McCartney's infamous slip dress) and I can never get enough of the old " New Look" that Dior made the staple of 50's fashion. I also Love the tailored suits that were hot in the 40's and tend to prefer flattering to comfortable, though I don't know what I would do without my jeans! Then there is American apparel, which is awesome for basics but there is always an element of WTF? when it comes to some of their dance wear, swimwear and bodysuits.
Staying true to yourself is always wise, as a musician if you change too much to follow trends you will be a "sell out" as an artist you will be "unoriginal" and in fashion, as a person you may be a "trend whore" or a "slave to fashion"- whatever. Those are kind of rude. What I try to avoid by staying true to myself (and yes I can wear some really unusual things sometimes) is looking back on pictures and thinking "I can't believe I wore THAT!"
So take care, and stay true to yourself in all endeavors!