Here's Those Three Reasons:
Don't Lose Money
If you're not tracking income and expenses from day dot, how can you be sure you're not spending more than you're earning? How can you know you're making a profit? You need to know this so that you can plan your exit strategy, right?!
Stay on Track
Are you tracking deadlines? What about how much time you've got to spend in your creative business? How do you know what to charge if you don't know how long something's going to take you? Smart freelancers are doing this — are you?
It's All in the Contract
No matter what you're doing, if you're working with a client, you MUST have a contract in place. Without a contract, you're relying on the client to know when to pay you — not great for you if the client is super busy and forgetful… Get that contract in place BEFORE you start your work!