We have over 30 hours of video lessons, over 2000 practice questions, and over 1500 vocab flashcards - all of which you need to complete if you're aiming to get a high score on the GRE.
Completing these will require 100-150 hours, and depending on how many hours you can spend per day, and how many study days you have per week, it can take 4-12 weeks to finish the course completely.
It is recommended that you choose the 6 month plan so that you will have enough time to complete the entire material, and also make room for days or weeks you may not be able to study due to exams, or other reasons.
After signing up for a CrunchPrep course, you can download a suitable study plan and follow it regularly.