Students typically wait until the last minute to begin studying for tests, and many parents support this practice, fearing that their kid will forget the material if they review it too early. But decades of tutoring as well as personal experience has taught me otherwise: Consistent, deliberate practice over time is the way to master material.
I have 30 tutoring students, and bunches of them go to the same schools and are in the same classes. This means that I often have multiple students taking the same test on the same day.
Recently, I was working with a number of students who were all getting ready for the same Monday algebra test (the test was being given by more than one teacher at the same school). My weekend schedule was so hectic that, in order to find enough time for everyone, I met with some students after school on the Friday before the test (my least popular time slot as you can likely imagine). The rest of the kids reviewed with me on Sunday.
This arrangement accidentally created a nice mini-experiment, with interesting results!