<p>It really depends on the class. Easy classes might take just an hour or two outside of class, except before midterms. Hard ones might take 15 hours a week or more or outside work for 3 credits. </p>
<p>I am in engineering classes and most of them have a weekly assignment. Midterms require more work, though if you were to be disciplined and study more than a few days before the midterm, you could have a consistent load. Other majors have more papers and fewer assignments.</p>