We wore ours (with ribbons underneath of course) M-F 9-5 (or whenever you were done with school). That was pretty standard for all the sororities on campus. We also were allowed/supposed to wear it with everything - thank God. DZs had to wear theirs with dress pants or skirts only (in other words they had to dress up for school for 6 weeks) so that made me certain that DZ and I were not meant to be.
