If you are planning to take the GRE, chances are that you have already invested a lot of both time and money in preparing for your career, and you are getting ready to invest even more. Therefore, preparing for the GRE is the last place you want to try to skimp or cut corners.
A perfect score on the GRE is possible, but very difficult to achieve on your own. For one thing, the GRE is comprehensive, and doesn’t provide leeway for weakness in any area. Particularly for students whose majors are not in mathematical or physical sciences, the Quantitative Reasoning section of the GRE is likely to include mathematical concepts and techniques that they have never actually encountered in their undergraduate math curriculum, or that were covered only superficially. Chances are, for almost everyone taking the GRE, you will have to develop new skills, as well as refresh ones you have already developed, in order to achieve a competitive score.
For another thing, preparation for the GRE almost never takes place in a vacuum; it usually must be fit in to a busy schedule on top of existing responsibilities. Fortunately a good coach can provide guidance to make the preparation process easier, faster, and much less stressful, helping to overcome the hurdles that prevent many students from fully applying themselves to preparing for the GRE.