No pain, no gain. A diagnostic test helps all of us, including you, make informed choices about your situation. The test, based on the actual test format, helps us pinpoint the topics and subtopics at which you excel, and even more importantly, the areas at which you can do much better. It also gives us a glimpse of your current endurance levels; remember that the SAT is nearly four hours long, and seeing a test result will give us invaluable information about how much we should push your energy levels.
Given unlimited time, most people will be able to solve most SAT questions. But it’s important for us to know how much your accuracy levels go down when you’re under time pressure. In addition, remember that diagnostic tests are the most reliable indicators of whether you are more suited to the SAT or the ACT.