Two moths should be enough if you recently graduated or your pretty fresh with your content material. Even a month and half should be enough just for questions as you will find yourself feeling exhausted at some point. Anyway, I spent 4 weeks M-F answering as many questions as I could. Some days 50 some days 200. I purchased NCSBN for 3 weeks and did their questions. Then for the last week I used LaCharity and NCLEX-3500 online version. Hope this helps. Good luck to you!