The number doesn't have to be right, but you should be prepared to defend it intelligently. Just as important, they will help you take the employer along with you. So give yourself an attitude adjustment. Most people treat an interview as if it were an interrogation. The employer asks questions, and the candidate gives answers.
Headhunters go out of their way to avoid that scenario.
Candidates who think of themselves as employees immediately tip the scales of power in their favor, because they come across as people who understand the job and who are prepared to do it. Doing the job causes the most rapid shift in control that I know of. To win an offer, do the job. Zagorski, now 40, walked over to the VP's whiteboard and outlined the company's challenges, as well as the steps that he would take to increase its profits. Fifteen minutes later, as Zagorski wrote down his estimate of what he would add to the bottom line, he looked up at his interviewer.