I registered for the general GRE a couple months in advance. But unlike many of the people on this thread, I didn't so much as look at a practice test. Or study for the test specifically in any capacity. I completely winged it.
I suppose for the math GRE, I looked at a practice test and vaguely remember doing a couple problems?
Final scores: 169Q /161V / 5.0W, mGRE:760
Percentiles: 96% Q/ 86% V/ 91% W, mGRE: 73-76% (depending on the year; it has been decreasing).
I regret not studying for the mGRE more. What I did was take some of the courses shortly before taking the mGRE so that the topics were fresh in my mind. Weird how there was a lot of abstract algebra on there.
But anyway, there a couple reasons why I don't study for these kinds of exams. The first was a misplaced idealism and self-righteousness where I believed these tests are designed to test our competence in these areas as they had developed in college, and to cram for the exam would be disingenuous, because it would inflate our scores to a point that was not reflective of how competent we actually are. But screw that, multiple choice tests aren't really super reflective of competence anyway. The second reason is because I just happened to be drilled on multiple choice tests since I was 6. It wasn't even kaplan or some other test prep service. There were just that many scantrons and multiple choice tests for a decade and a half.