А это про трехлетние тренировки (не учебу в заведении, а именно тренировки) для авроров после Хогвартса.

‘Well, you’ll need to demonstrate the ability to react well to pres­sure and so forth,’ said Professor McGonagall, ‘perseverance and dedi­cation, because Auror training takes a further three years, not to mention very high skills in practical Defence. It will mean a lot more study even after you’ve left school, so unless you’re prepared to -’