When you enjoy fame and fortune, every look change is always very well planned. The change could be for promoting a new job and, in the case of actors, for playing a specific part.
But everything should be meticulously thought out. The change of hairstyle should fit in perfectly with the future artistic projects of the celebrity in question.
For this reason, when something fails with their hair, it may even end their career, like what happened to Keri Russell with "Felicity".