I would not have been able to clear the CIW User Interface Designer certification exam if i had not opted for the mock exams on the first day of the preparation itself. I used to study the syllabus and the topics within to learn more about the certification. I was not aware of the format of the exam, the type of questions asked and also the time duration and the scoring system. But practicing on the mocks made me so conversant with all this that i could easily attempt the mock and remember everything. I did not refer to the file again and again.