Okay, I agree with mnmaa with this one!
For Chemistry and Biology, you MUST understand the concepts and theories and grasp a deeper understanding of, and learn how to apply them to various question in order to attain a mark in the high band range! My friend ALWAYS memorises concepts and theories for Bio (word to word). However, I only read over to grasp an understanding and summarise it in my own words. End Result: I always beat him by 5-6 marks because I understood the concepts and can relate it the question.
However, for Ancient History, it is purely content and so one MUST memorise as well as understand the concepts and content... OMG! Have to memorise 60 pages of notes + 10 pages of quotes + evidence for 2 topics!! 3 more to go
For English (Advanced, Extension n Stnd), it is best if you do not memorise an essay as it will be arduous for you to mould into the question if you are not flexible. That said, it is always a good idea to have a prepared response in case it fits into the question, so you conserve time
I only memorise notes and certain phrases when preparing for essays! What really helps is... it is OBVIOUS... practicing past papers and questions -
In precis (lol), memorising can be helpful, but not beneficial in the long term run as understanding the concept aids an individual 'mould' it into the question better