Therapy is very useful, and can be especially important for FTM patients. A man who starts HRT and realizes that it wasn't the right option after a few weeks or months won't really suffer any long term effects. A woman who realizes that it was the wrong option though will experience changes almost immediately; increased body hair, deepened voice, hair loss on the head, and so forth. The therapist can help to determine whether it's really the right option for you, and can help you to make the right choice.