Does the amount of writing matter in exams?

For example, in most of my exams ( I guess I'm a borderline A grade student), I write soooooo much, mainly to fit in as many answers as I can and hope that I can get full marks on that question! But in the actual exam, will it be permissible to write lots and lots, but not writing outside the box? Like, will I need to change my handwriting style to write small so I can write lots? Thanks =D

It's the quality of what you write, not the quantity if you write less but something that is more relevant to the question you would get higher marks. If you blabber on for 3 or 4 pages of less relevant information not required you are less likely to get a good mark. I got an A in my History mock after writing 10 pages double sided but I know lots of people who wrote about 15 and ended up with B's and C's.