I don't see any problems with studying 4 days a weeks.
If you're looking for a way to organize your studies, you might consider signing up for Beat The GMAT's free 60-Day Study Guide (https://www.beatthegmat.com/mba/gmat-guide). Over 40,000 Beat The GMAT students have already done so.
Each day, you'll receive an email with a series of learning activities that guide you, step-by-step, from Day 1 to test day. This will ensure that you will cover everything that the GMAT tests.

Here's an outline of all 60 emails: https://www.beatthegmat.com/mba/gmat-guide-outline

Cheers,
Brent

By the way, have you taken an official practice test yet (https://www.mba.com/the-gmat/download-fr ... tware.aspx)?

I always encourage students to take a practice test VERY early in their studies (within the first week of preparing). I do this for several reasons:
- Students should know, as soon as possible, exactly what they will be preparing for over the coming weeks and months.
- The results of this test help students gauge the amount of work required to reach their target score.
- These practice tests help build confidence, since scores inevitably improve as the student prepares.

If anyone is interested, I wrote an article on taking a practice test early in one's studies: https://www.beatthegmat.com/mba/2013/05/ ... st-already

Cheers,
Brent

Hi november22,

Studying 4 days a week is fine - there's nothing inherently good or bad about that idea, as long as you are productive with the time that you spend on your studies. The real questions involve HOW LONG you're planning to study and your SCORE GOAL. Planning to take 21 CATs is really not necessary though - you would be better served doing more practice problems and review than taking lots of CATs.

GMAT assassins aren't born, they're made,
Rich