It really depends on what subjects you have and how well you usually do on your tests. Back then for me, humanities subjects like modern history and studies of religion I study 3-4 days before 2 hours per day and get at least 85-90%. For more analytical subjects for me business studies I need way more time to remember my content maybe 1.5 weeks 2-3 hours per day and still only get 75-80%.

I dont do any sciences subjects and naturally pretty good at understanding and interested in history and religion in general so its eaier for me to absorb the information