I've repeated year 12 for health reasons. It was a surprisingly easy decision to make, because at the time I was so sick that I'd only go to school once or twice a week, and then most of that time was spent in the sick bay or leaving home early. Not only was it taxing on my health by staying at school, but the teachers couldn't afford to waste lesson time ensuring I was ok. So, I left school and had seven months to recuperate. The hardest decision was whether or not I should try for my hsc again, and if so, at tafe or my old school. In the end, there wasn't really any doub - I was always going to get my hsc, and I'm very proud to say that graduation is FINALLY here next week! It's been hard, but worth it.
Any particular reason why you want to know?