I just signed up for a course where I thought I’d have to decide between a weekend morning or weekday evening. To my delight, the prof just wrote back that the same material is presented twice each week, in discussion/seminar format. On any given week I can choose to attend either day. I care more about the subject matter than consistency with other seminar-mates. Above all, my adult responsibilities make each week different, and it’s mostly out of my control, depending on what happens to others in my family. I never know until I’m in the midst of the week which day will work better for me. Not having to declare which day, ever, is just ducky.