90 days is ideal period to study for GRE to get best possible score. But the period is long enough to lose your motivation and momentum. So the plan must be made flexible enough to avoid any possible disruptions such as work or family commitments to your study schedule. The schedule is divided into two parts. First part will focus on mastering the strategic approaches to each type of question on the GRE which includes vocabulary and math content knowledge and getting the answers to the questions right. The second part will focus on answering questions quickly and challenging yourself with tough questions.
- ETS Official GRE Guide 2nd Edition