Yup. When I notice that I won't learn much from a course or the subject doesn't interest me I skip the lectures and the day before the final I go through the book with 100% of my focus on "is the paragraph or formula I'm reading now going to help me pass this course". This allows you to skip tons of stuff and gets you much more bang for the hour. I've noticed that most other students just mindlessly read everything and as a result don't remember or understand the important stuff.