As a child you were probably told, don’t touch the flame. You were probably told, don’t play with sharp implements. Many of us did anyway, suffered the consequences, and learned the hard way. As you study you are likely to answer a question incorrectly. Keeping note of your weak areas allows you to learn from your mistakes. The philosophy of Dr. Gleim is that you actually learn as much, if not more, from understanding what your mistake was and why you made the mistake than getting the answer right in the first place. The best time to make a mistake is during your preparation, so you don’t make the same mistake on the actual exam.