The relationship between a band manager and a musician is just about the most important (business) relationship either party will ever have. Misconceptions swirl around this oh-so critical connection, however. If you're thinking of hiring an artist manager or breaking into the world of band management yourself, cross these music industry myths off your list.
If you are a musician, managers are important because they free you up to work on, well, music - and that is YOUR real role in all of this. It is also true that when you get to a certain level, labels, promoters, agents, PR companies and so on will prefer to deal with a manager instead of you. Sometimes these people need to say things about a musician's work that a musician might not like to hear - so they prefer to the let the manager do the dirty work for them.
However, in the early stages of your career especially, don't feel like you need to get a manager before you get a enough songs to fill a set at a show or before you even have your first practice. In fact, people within the industry will take you less seriously if you have one of those "managers" - i.e., a friend who calls themselves a manager and does absolutely no managerial work - than if you go in representing yourself.
There's a big difference between your friend who decides they are a manager so they have an excuse to get a seat in your van while you're on tour and your friend who decides they are a manager because they're so excited about your music they think everyone should hear it - and they decide to make that happen. An enthusiastic, though inexperienced, manager with a solid work ethic can do big things for you, even if they have to fight every step of the way to establish contacts and get people to pay attention to them.
More established managers bring more connections, and they can often get things done more quickly. But they're hard to attract early in your career, and you're unlikely to be their first priority. If you have a chance to get some enthusiastic hands on decks when you need some help, go for it.
Artist-manager relationships should be collaborations, not dictatorships. When you're selecting a manager, it is critical to make sure that you share the same vision and have the same expectation about the music career you're trying to build. If your manager is trying to mold you into something you're not and pursuing opportunities you're not sure you actually want, then you may have the wrong manager working for you.
Established managers surely do bring a world of experience to the table and definitely have valuable advice to give about how things work in the music industry than an up and coming musician would do well to take on board. However, that doesn't mean you have to sacrifice your sound and your ides about your music to fit into some supposed framework. The right manager for you will help you maximize the things that you're doing to increase your chances of music industry success, not try to make you into a whole different act so you can get a record deal. Remember, a manager is a partner, not a boss.
The flipside of the above is that when you have a manager, you do need to include them in decisions you're making. No manager likes to find out about a show, new song, interview or some other big thing through another party. It makes them look bad, and it makes them feel like they're being cut out of your career. If you're negotiating for payment for something, your manager should also be involved - after all, they get a percentage of the money you make with your music as payment for their work, so they should know about any little side deals you're trying to work (which can often be a bad idea, anyway).
You don't so much need your manager's permission to do stuff - though you likely do need their OK to sign certain deals - but it's more of a respect thing. Again, remember, this is your partner. They need to be in the loop, or they can't be effective helping you.