I've seen people at song circles that didn't use books still dither when it came time for their turns. It may drive me up the wall, but I figure that's how they are. I've seen others use books without too much wasted time. I have participated in a regular workshop where one of the performers (who should have known better), showed up, had to tune their banjo and then still decided what to do. And that was at a festival with other performers waiting to do their turns and a fixed time allotted.