I spent a lot of time in the computer lab waiting for my roommate to figure out that CS was not the degree for him. I got a pretty good census of the sorts of things that other classmates got stuck on, probably informs my strong feelings on the value of quality tools over just tools.

There were certainly a lot of people who didn't really understand the question, and I couldn't really help them much without risking the poorly worded guidelines on what would earn you an expulsion, but there were a lot of people spending a lot of time banging their heads against typos and simple structural errors.

I learned early on that the facts and tasks I biff on are often the things I remember the clearest later on, but also that most people are not like that. They remember the things that they got right easily on the test. I'd wager that for most of them, that time spent wrestling with the computer provided very little to no growth opportunities at all. 10 hours on a homework assignment might have yielded at most 90 minutes of actual progress.

A good rule of thumb is to average 2-3 hours out of class studying for every hour spent in class.

For the more difficult classes, that number can be even higher.

So for a class that has 3 hours of lecture time per week, that's 9+ hours per week on that subject alone.