While it's almost never too early to take the test, the benchmarks listed above are given by the tests' respective administering organizations; you should contact the admissions offices at your prospective schools to verify their exact time requirements. That said, no school requires test scores less than two years old, so you could take your entrance test one or more years in advance of beginning the application process. This not only gets one major requirement of your application out of the way, it also gives you a nice, wide window of time to squeeze the test into your busy schedule.
If you're an undergraduate junior or senior, consider taking your exam during a natural lull in your course work; shortly after a semester has started or during the summer months, for example. If you're a post-graduate, your test should be done when you have the fewest demands on your time, since preparation usually requires a substantial commitment. Plan on devoting twenty or more hours of preparation for the GRE and GMAT, more for the LSAT, and even more for the MCAT (depending on your current mastery of material) for significant score improvement. |