I did AS last year
English: Just doing the homework really, and a few extra essays. Very little revision (got a B although if remarked I think it would have gone up to an A, after having seen the breakdown and stuff. Whatever, let's just say it's a B).
Applied ICT: We had no teacher and I learnt the whole subject 2 days before the exam. So I revised 9-10 for the subject in a whole year (because I studied 9 hours split in 2 days, I barely even opened the book before that. When I got to the exam my mind was steaming with all the info. One day later I had forgotten everything). (got an A)
Physics: very little. Except for the occasional test throughout the year (I'd spend around 2 hours revising for each test), I didn't spend much longer than an hour a day the week before exams, or even less than that. (got an A)
Now is when it gets drastic:
Chemistry: I must have spent well over 1 hour of revision a day for this subject for a month, as my board, CIE, is obsessed with organic chemistry, and the amount of stuff there was to learn on this was unreal. In the end, my paper turned out to be one of the papers with less organic chemistry in CIE's history, so that was a major screw up as I spent 90% of the time revising for organic chemistry. Got an A.
Mathematics: I did every single past paper there was to do from 2005 to 2013. All components, for every time zone (CIE has a paper for 3 different time zones). By the end of the exam period, exam papers were coming out of my ears. Got an A.
So yes. I did very chilled revision in April, studying a bit of this and a bit of that. Then I started doing past papers and noticed I didn't know as much as I thought. So May was basically a month of manic revision. If you work hard you'll get an A in your subjects. I'm certain that even if my paper was marked incorrectly, had I done just a bit more of revision for English I would have gotten an A.
As for A2, I'm doing Maths, Chemistry, Physics and Further Maths (which is self taught).
I'm trying to keep a good, consistent pace of work and I'm doing around 1 hour of revision a night for all of my subjects (that is 1 hour between all of them, not individually) but Further Maths, which I'm having to revise over 1 hour and 30 minutes a day independent of my other 3 subjects as I'm self-learning and in a single year).
Work hard, it is gratifying to know the hard work pays off.