I went over the destroyer once and twice for the math section. Then I took 3 achiever tests just to get a feel for the real test. Once a took the first achiever, I realized that my performance in QR was a little worse than that on the destroyer because I was pretty much burnt out sitting in a same place for such a long time and focusing on the screen. I recommend that at least one entire practice test before the real thing. I took mine 10 days before the real one because I had only a month to study everything after graduation and before the test