Showing up to class respects the professor’s time and benefits students who are looking to learn the material efficiently.
Just as class structure greatly varies, so too does attendance policy. In your first week of the spring semester, you’ve probably experienced an onslaught of syllabuses and class introductions, and more often than not you’ve heard the professor say that attendance is mandatory, or at least recommended. This might be more true in some departments than it is others, but I have a hard time imagining a professor who does not consider the student’s presence in the classroom to be more conducive to their academic success than their absence.
In my freshman year, I slept through the same 8 a.m. class every day I had the chance. The presentations were put online; the homework was emailed out to us. I came in for exams, and even then dozed off during the final. I got a B in that class and I didn’t deserve much better. The fact is, I probably deserved worse.
When I tried the same thing in a calculus course, I discovered the professor would be grading according to his own methods of solving the problems. I practically failed the first exam, and spent the rest of the semester pulling my hair out from the stress of playing catch-up. In a lot of classes where attendance is optional, you have a chance of doing just fine, but you might have a much greater chance of finding yourself up shit creek without a paddle.
Even if you feel you’re a competent enough student to ace a class you’ve hardly ever attended, consider having some respect for the professor. In some of my classes, I’ve seen the student population thin out to a third of its actual enrollment, only for a grand reunion at the midterm and final (and their respective reviews). The professors in those courses were visibly dissuaded by the low attendance, and sometimes I even felt the energy of the lectures die down with such a small audience present. I felt a lot of sympathy for my professors; as enthused and knowledgeable as they were of their course material, the students were unappreciative. Learning is a partnership, and students who don’t want to show up to class and expect an A anyway weren’t holding up their end of the bargain.
So, if by some miracle you find yourself in a class where the professor could care less if you were present, the class size is large enough your absence won’t have a real effect on the overall population of the room, you are familiar enough with the course material and the professor to pass the class without ever hearing a word spoken during actual course hours, go ahead. But even the one time that was true for me, I regret skipping. I wasted a lot of time rolling over presentation slides outside of class, and wasn’t learning as efficiently as I could have been had I been present. In other words, it was a waste of my time to skip the class.
Without sounding redundant, it’s for practically everyone’s benefit that you get that ass to class.