Let's say you're working four on/three off. What are your preferred days of the week to have those three days off? In the past, I've bid my days off around bar nights, and in July I'm going to bid my schedule around the local minor league team's home games. Since my wants change from month to month I generally don't care which days I'm off, but with all other things being equal I prefer being off Thurs/Fri/Sat.