Tasks such as reading, writing essays, researching, doing maths problems, etc.
are best done at home, away from the distractions of other students.
So the amount of homework that is reasonable depends on expectations and on willingness and capability of students to learn - learning is not passive, and some students are going to learn quicker, some slower.
It is likely, given the recruiting process, that students at (say) Duke are going to put more effort into a class than students at a community college, not only because of their backgrounds but because of their financial and family situations.
Some schools and some countries don’t bother with homework at all, and their results do not seem to suffer from it.
Studies show that homework adds nothing to standardised test scores for primary/ elementary pupils.A problem with homework is that you don't know who actually does the work; in K12 so many parents get involved now, and group activity is common (when it isn't supposed to be), so it becomes difficult to know whether the student is learning anything him or her self, and even more difficult to make a formal assessment.Formal assessment is crowding out actual learning as it is, thanks in part to government regulation, in part to people who think teaching is only conveying information (which is a minor part of good teaching).The ultimate question is, is there time to do all that needs to be done, during class time. Homework has little educational worth and adds nothing to the time spent in school.Homework is almost always done when a child is already tired from a long day at school.As a result few students are at their best when they sit down in the evening to yet more work.Yet this idiot charged ,000 a day as a consultant, according to the newspaper report.Homework for homework's sake should not exist.Doing tasks linked to recent lessons helps students strengthen their understanding and become more confident in using new knowledge and skills.For younger children this could be practising reading or multiplication tables.