It depends on your hair type and personal comfort. You must wear your hair to regulations. Officially, it can't be longer than the lower part of your collar but for beast they may make you put it up so it doesn't touch the collar.
Hair ties and hair clips must match the shade of your hair. Buy lots and lots and bring them - if you are a blond or redhead you might not find matching clips in the C-Store.
My daughter cut her hair and donated it the week before. She got a pixie cut that worked for her as she has fine hair. The cut was wash and wear and she required no clips going into Beast. A girl we know saw her hair the day before and went that night to get hers cut too. They both said they were glad they did.
My daughter is now growing out her hair and will probably let it grow long again.
Keep in mind - you don't want to be bothered with hair falling in your face, and you will be undergoing a tremendous amount of physical excercise. You also can't be fussing with it during the day.
The week before the Marchback you will go into the field and basically "camp". You will not have access to a shower or shampoo during that time. Shorter hair can be much easier to care for out in the field.
If you keep your hair long - I suggest having it all one length. Practice, practice practice. If you know some girls who do sports and put their hair in a bun get them to teach you how to do it with two hairties and some clips.
You must show up for R-Day with your hair in a regulation style.
