There are different types of managers in the entertainment industry; the most common are Personal Managers.
Ideally, a Personal Manager takes care of both the personal and non-personal aspects of the artist career, he/she should be the link to the entertainment industry (with sold contacts), and he/she must be able to assist the artist in putting together a creative team, recording package and marketing plan that will best showcase the artists ability and talent to the target audience.
Personal Managers are essentially glorified middle men (woman) who handle the day-to-day business of managing the artist career by acting as the artist’s liaison and interfacing with personnel in the artist relations, promotions, and marketing capacity. They should be the central coordinator for the release and marketing of the artist album, the tour schedules, and the artist’s publicity campaigns. This is done so that artists are able devote more time to the creative aspects of his/her career.
Here’s the bottom line, if you want a personal manager to manage your life, you may end up being considered a Star or a F**k up, it's a Crap Shot. Usually, when one relinquishes power they are subject to abuse (that sometimes last up to 7 years), personal managers generally have the ability to lock an artist into the best and worse commitments. So make sure you establish clear expectations, goals and limits with your Manager.
With that said, Managers are on this planet to make money and a decent living for themselves not to stroke egos, become relationship counselors, or bails bondsmen. In order for a Manager to survive, he/she needs an artist(s) to pull in over $20,000 worth of merchandising and shows per month (Based on fairly standard 10%).
Most artists I encounter make $0.00. So be grateful if I pick up your damn project, stop bitching over every little thing & when I tell you to do something get it done, it’s for both our sakes damn.