A well prepared employer has an interview manual including all the potential questions that may be required. Having your interview manual up to date saves you so much interview preparation time, and puts you in control of the interview immediately - thus you present as an organised professional future boss, which clearly is the impression you would like to give.
The other real positive about the interview manual is that you are easily able to ask multiple candidates exactly the same questions from exactly the same interviewing structure and compare not just the answers, but the path that the conversation leads to beyond the question.
Interviewing a potential employee is not just the questions and the answers, it's the consideration and thought process behind the answers. Well considered replies tend to indicate a higher level of preparedness and a higher level of overall consideration to situations.