How many hours a week do you need to spend for 4 courses?
As you'd expect, it varies substantially person to person. Nominally, each course should take up 12 hours per week, including time spent in class (n units means n hours per week spent on the class). In practice, it can be anywhere from 50% to 300% of that or more. Most people at the extreme top end of the range end up dropping the class, so the top side is pretty well bounded.
Are there any known people who go to these hard courses without spending as much time as supposedly required?
Sure. When I was a TA (for an advanced control theory class), there was a huge range of time spent. Some people never showed up for class and did great; others came to every class, recitation, and all of my office hours (that alone constitutes ~10 hours per week) and reported spending another 6 to 10 hours on each problem set, and probably double or triple that on each lab.
Most of my undergrad career I took 5 classes a term, and I did my absolute best never to study from Friday afternoon until Sunday afternoon. As long as I stuck to my schedule, it was completely doable. Of course, I skipped classes and recitations that I found unhelpful in order to reduce wasted time.
As you'd expect, it varies substantially person to person. Nominally, each course should take up 12 hours per week, including time spent in class (n units means n hours per week spent on the class). In practice, it can be anywhere from 50% to 300% of that or more. Most people at the extreme top end of the range end up dropping the class, so the top side is pretty well bounded.
Are there any known people who go to these hard courses without spending as much time as supposedly required?
Sure. When I was a TA (for an advanced control theory class), there was a huge range of time spent. Some people never showed up for class and did great; others came to every class, recitation, and all of my office hours (that alone constitutes ~10 hours per week) and reported spending another 6 to 10 hours on each problem set, and probably double or triple that on each lab.
Most of my undergrad career I took 5 classes a term, and I did my absolute best never to study from Friday afternoon until Sunday afternoon. As long as I stuck to my schedule, it was completely doable. Of course, I skipped classes and recitations that I found unhelpful in order to reduce wasted time.