The CrunchPrep course has over 200 video lessons touching every concept that you need to know in order to ace the GRE exam. Although recommended, it is not entirely necessary to watch every video that is included in the course.
You’re free to decide which videos you would like to watch, and you can watch them as many times as you want. You can also choose to not watch videos concerning topics and concepts that you’re already confident of.
It is recommended that you make the best use of the time available to you, and to not waste it learning concepts that you already know very well.