[FONT=PrimaSans BT,Verdana,sans-serif]In contrast to blz, I found it very helpful to do random questions on Qbank early on. I did some subject specific questions after my class exams, only .[FONT=PrimaSans BT,Verdana,sans-serif]about 50-100 per subject, and then switched to random during dedicated study time. I think it depends on your study schedule--I didn't finish going through everything once until the days before the test, so I didn't have the option of waiting to do random tests til after I had reviewed everything like blz. Also, I think Qbank it not the best for assessing knowledge but can be a great learning tool, and so I really liked learning about things in increments with Qbank--a Qbank question or two before I had studied it formally, formal study, and then a few more questions from Qbank and/or NBMEs. You do feel kind of like an idiot at first, but Qbank managed to make me feel like that even if I had studied the subject, and you can see your progress. Most importantly, I think doing random questions while studying other subjects gives you little reminders of subjects you studied a while back or haven't studied yet, and at least for me I needed all the little reminders to cement that much information in my memory. So, it depends on you--if you have enough time after reviewing everything to do a lot of questions and/or want to use Qbank for assessment definitely go with blz's advice, but if you won't have much time after reviewing everything and/or want to use Qbank as a learning tool try doing random questions now..