Hi ls95,
Your particular 'needs' and study plan will depend a great deal on your current skills, strengths and weaknesses - and it might be that you end up needing more time to study (and more resources) than you initially plan for. That having been said, taking FULL-LENGTH CATs (with the Essay and IR sections) under realistic conditions IS an essential part of the GMAT training process, so you should be taking one at least every few weeks (and as you get closer to Test Day, you should be taking a CAT every week or so).
All of that having been said, since it sounds like you're just beginning your studies, then it would be a good idea to take a FULL-LENGTH practice CAT Test; you can download 2 for free from
www.mba.com (and they come with some additional practice materials). If you want to do a little studying first, so that you can familiarize yourself with the basic content and question types, then that's okay - but you shouldn't wait too long to take that initial CAT. That score will give us a good sense of your natural strengths and weaknesses and will help provide a basis for comparison as you continue to study. A FULL CAT takes about 4 hours to complete, so make sure that you've set aside enough time to take it in one sitting. Once you have those scores, you should report back here and we can talk through how best to proceed.
I'd like to know a bit more about your timeline and goals:
1) When are you planning to take the GMAT?
2) When are you planning to apply to Business School?
3) What Schools are you planning to apply to?
4) Going forward, how many hours do you think you can consistently study each week?
GMAT assassins aren't born, they're made,
Rich