A haircut is required if one is looking to change one's hair style or to simply just have less length in one's hair.
Sometimes one can keep the same length and just have it thinned out.Hair grows on average half an inch every two months. So to keep the hair from getting longer one must have it cut regularly. If one keeps one's hair short the growth seems faster as half an inch on one inch hair length is 50% of what you started with and much less if you started out with 10 inches. On the other hand a half inch mistake on ten inches is a lot more forgiving than on shorter hair.
A good haircut will look its best in two weeks after the haircut when it has had time to adjust. Curly hair especially needs some time to adjust to the weight difference.Pictures are the best way to describe a the style you want.
One of the latest hair cut these days is the Shag its flatering to most shapes of the face.