One of the first things a musician needs to do, assuming he or she is serious about a career in the field, is to determine the best business structure for themselves. Businesses become incorporated because this limits the liability to the individual owners. Most people would think--what could happen if you just play or write music that would hurt me as an individual? It's pretty easy to think of a lot of things: an accident driving to a gig, a claim that you've taken someone's copyrighted music and subsequent lawsuit, an accident at a gig--the worst one was the fire at the club in Rhode Island. So starting a company is a good thing, because if something bad happens, you're private investments like homes, savings, etc., won't be lost. It's like a firewall between you as a person and you as a performer.
The options are partnerships, Limited Liability Companies (LLC), and corporations such as S-Corps and C-Corps. The most popular today are LLCs.
Starting one is relatively cheap and easy--usually less than $1,000. For an individual, this is a no brainer. You have to keep separate records of your income and expenses, and you'll find a lot of expenses qualify as business expenses. Trips on the road, buying new music, DVDs or video games--all are business expenses when you are in the music industry.
For bands, it gets a little more complicated. How do you split the income from the band? Who owns how much of the company? One suggestion is for each band member create an LLC and have them own parts of the band LLC. It gets complicated, but so does life. Imagine if your band created a company and the drummer dies for some reason. Does the drummer's wife now become a part owner of the band?
Did you know that most movies are created as unique LLCs? The partners are all the companies involved in its production. You could do the same for a U.S. tour, pretty much anything.
I guess the final message is don't procrastinate and develop a business strategy for your career. An important part of that strategy is determining the best corporate structure for your music enterprise. Ask as many people as you can for their advice and go for it!