I went to a college that had a two week shopping period. I used to go to ten or so classes before deciding which one I’d actually take. I think I went to the first two weeks of Music 1 more than once. I loved the class, but it always conflicted with something else more important and that I was also likely to do much better in. After freshman year I always took an extra course, but I usually took it pass/fail. We weren’t charged extra so it was no big deal. I don’t know what the drop dates were because it never was an issue.