I read a lot of books at the same time, and unless I'm absolutely fastidious about making sure that I read all of the books every day, I end up with books sharing lines on the calendar. I find this a lot harder to read and understand (particularly when the colors for the bars are quite similar, which tends to happen a lot on my calendars). I'd really prefer it if each book had its own row until it was completed, or at the very least, if different books maintained at least one space between them so that they don't butt up against each other in a way that makes it look confusingly continuous.