This has been a long running question.
If you have extra money to splurge on seasonal trends - do it.
But if you want long-term use of your pieces, find your style. Get signature pieces that reflect you.
I personally think it is a waste of time and money to follow a jewelry trend. You know what you like and what looks good on you. If you don't, ask a friend for some input.
When you find your style, stick to it. Invest in pieces. It may cost you a little more upfront but you will get more wear out of them and I guarantee more compliments.
Here's a little quote from a woman who knew what it was all about....
"Fashion Changes but Style Endures"
- Coco Chanel