I usually aim for around 3 hrs on a school day (+ any study periods - I've got quite a lot), sometimes 2 if I'm rlly tired. On weekends I average 5 hrs a day.
Honestly, I think you should just figure out how long you can sustain productive/efficient study per day and do that. It also depends on your subjects and how mentally demanding they are. You do quite a few difficult subjects
I'm very inconsistent after school icl but on weekends is where you see the big numbers like 7, 8, 9, 10, etc. Anything more than 4 on a school day is rare, usually 2-3 ooops
zero
i have never studied except the night before and immediately before my prelims and have so far done ZERO hours of study for either of my hsc subjects