“How long until I find out if I booked the role?” This is something that can make actors very nervous. I’m sorry that there is not an easy answer. It’s like my lawyer said when I was negotiating a real estate deal, “How long is a piece of string?” It all depends on the time frame of the project, the director’s mood, and the amount of producer and network approvals needed. 

Sometimes the director approves and they're just waiting for some guy sitting in an office somewhere in Burbank to sign off. 

Recently I was casting an HBO pilot and one of our actors was told that she would  hear from HBO with an offer. Well she waited ten long days and gave up other work in the meantime. Finally I called HBO, and the problem was simply that the business affairs office hadn't moved it off their desk yet. 

Remember that priorities are different on the other side of the deal

My advice — once you’ve done your audition, put it out of your mind, and develop a hobby to distract you while you’re waiting.