such as the following, you do not want to take training with a vocal coach if…
1.They are not familiar with or can’t identify your throat from a medical point of view.
2.They do not value the medical grounds.
3.They impose you ‘their’ theory without the scientific grounds.
4. They always brag about their success.
5.Are too emotional
6.They always speak ill of other vocal coaches.
7.They force/push you to buy their book and/or goods.
8.They ask you to them loan money.
Note:You also have to be a good student, punctual and dedicated, if you want to get the most out of vocal training. Most vocal coaches just teach you through their own way on the basis of their experience.
Their methods are not wrong, but you won’t know whether their way is suitable for your throat or not unless you actually take training lesson once or even continued with them.
It is common with successful people in the music industry to have gone through training with many different vocal coaches before. Therefore, the learner also has to judge if their coach’s methods are producing results and if the training is appropriate or not.
You should quit and look for another coach if you are ever with a coach, whom’s training does not fit you or your goals.