When you choose a hairstyle you will want to accentuate your best features and minimize your least favorite .
For example if you have larger forehead, you might want to have fringe.
But if you have the most beautiful eyes you must dont want to cover them up with hairstyles with long fringe.
Hairstyles for rounder faces would normally be longer to minimize the width of your face.
A hairstyle for a longer faces could be shorter with fringe to give your face a wider appearence.