In my experience it varied from professor to professor. Many professors would notice when you don't attend lecture, which I found to be impressive given the siz

In my experience it varied from professor to professor. Many professors would notice when you don't attend lecture, which I found to be impressive given the size of some of the classes. I found that some professors were more likely to be lenient or accommodating if they recognized you as a frequent and engaged attender, or if you went to office hours or asked insightful questions during lecture. On the other hand, there were classes I didn't attend very often at all, and I remember a couple of times being stumped on the homework and going to office hours to gain some traction only to be gently ribbed for not going to lecture. You get the sense that many professors do pay attention to that kind of thing and it does factor in, if only unconsciously.