If you wait to buy E&Es (which are over 600 pages long) until after school starts, you really won't have time to do as much with them.
There are going to be people who end up buying AND reading them before, whether or not people admit to that. They will have a much easier time grabbing on to concepts and can do only practice problems during the year if they wish.
Don't take my word for it, check out this article. http://www.top-law-schools.com/success- ... chool.html
If you want to do some work, but not an outrageous amount, I would start by reading the Examples & Explanations books before school.
To each his own.