If you are producing at the 99 seat and under level, odds are you'll do it all. You may also put in your own money when it comes to a project. You'll be involved in casting, marketing, budgeting, and you may even find yourself sweeping the floor.
If you are producing on the commercial Off Broadway or Broadway level, a lot of your time will be spent raising money and securing investments. You'll also be hiring creatives and making deals with theatres and spending a lot of time with lawyers.
If you are producing one-time events or benefits you'll spend a lot of time making phone calls and writing letters. You'll go to a lot of parties, visit plenty of venues, and make many deals with companies for sponsorship.
And each of these things will define you.
When people ask for recommendations on producers, your name will come up in connection with what you've done. For example, I've produced in a lot of festivals, so I often get referred as a good festival producer. These references resulted from one year when I produced five shows at the same time in the same festival.
When you think about where you want to be in five years, I encourage you to think about the type of producer you hope to be. Sure there'll be changes along the way, but remember that the things you do now will define the projects you do later, so choose carefully. It's very easy in this business to be seen as one thing and the last thing you want is to be pigeon-holed.