Healthy singing an important part of helping you as a vocal coach is guiding you to reach a good, relaxed voice. As a singer of any kind, you need to stay in tune with your voice. If after singing you lose your voice, or your voice hurts, or perhaps your voice feels strained, this is not healthy. A vocal coach will help you to attain a healthy singing voice.
This help goes beyond just drinking tea or avoiding milk. A professional vocal coach will help you improve in areas you are weak, coaching you to sing for longer periods, to hold cords longer, and to expand your range of tunes. Poor vocal health could lead to things like nodules and phlegm, ruining your singing/music career before it even begins.