The general layout is start at 8:40am and finish at 3:20pm. Tues' and Fri's, I have 4U classes in morn from 8am. Mon arvo's, I have after school phys seminar run by my phys teacher, which I usually leave at 4pm. Wed arvo's, I have school commitment, (Yuck >.<; ) which varies depending on how much work we're given that day.
This is not counting all the first periods and last periods off I get. Start at half past 9 or so if I have first period off and finish at half past 2 for last periods off. Of course, if it happens to clash with 4U or after school stuff, I still have to get to school early / go home late. And my school's weird, using an 8 day cycle, so every week has different days off, which is stupid IMO, but eh -.-;