If you elect to get hair plugs, keep in mind that it's possible that some of them won't take. It's normal for the hair to fall out before it starts regrowing, but sometimes the hair plug dies and has to be replaced during a later surgical session.
The goal of most hair replacement therapy is to use the patient's remaining hair as efficiently as possible. This may require grafting, scalp reduction, skin flap transplant, and even tissue expansion. The new hair has to come from the patient to avoid rejection.