I saw on destinyliang's thing you wanna get 99.95. My advice to you for that, study every day. Even if for only 10 minutes. Just at least look at your notes every day. systematic daily study is what gets you there. And in terms of hours, its impossible to say, really smart people (IQ wise) dont need as much time to learn the same material, while less capable people need a lot of time. Just study as much as it takes before you can confidently recall everything in great detail, by dotpoint