I found out that retaining a little every week as you go along saves you a lot of stress at the end-of-semester exams, even if the little you retained is like 5-10% of what you need to know. I had basically memorised the topics of stereochemistry and spectroscopy/analytical techniques before the exam, so that I had the one week of stuvac to cram all of the other parts of chemistry. Not good for my health, but I was very relieved just to skim through the pages for the two topics mentioned above and be like, yep, I know this, even though they were a relatively small part of the chemistry course.
I agree with Lexi, my "few days before exams" snared me only Credits, but which I'm grateful for as I thought I'd literally fail everything (had nightmares of getting 49 since concessional passes are no longer awarded)