<p>I think audition coaches can be extremely useful, and depending on the resources in your area, may be a good investment. My D attended a regular HS, but was able to participate in both good quality community theater as well as a well regarded regional theater in our area. She took weekly voice lessons from the time she was about 12, but did not use a vocal coach except for once her junior year to get ready for a competition. She did not take acting until she got into college, but did get a lot of direction in her theater experiences. She did not attend any theater type summer camps or programs. While she tried to fit dance in where she could, theater rehearsals generally interfered and she got most of her dance in the IB dance program and the dance team at her high school.
The one thing she has is a LOT of audition experience which I think made her pretty comfortable in college auditions. She did not use a college audition coach and yet had good results with auditions. The program she did not get into was a non-audition program. </p>
<p>I think if you are in an area with limited resources and do not have a lot of experience auditioning for more than high school musicals, it would probably be a very good investment to work with an audition coach. They can give you a lot of help picking appropriate monologues and song, critique your presentation, and teach you tricks to feel more in control at auditions. However, there are a lot of kids who do not use coaches and see great college audition results, so it is definitely not a necessity. Just know your strengths and weaknesses, and use whatever funds you have to best prepare for college auditions.</p>