I realized that I never did my last post in my string of organizational posts, or ways to make your life easier and your students' excuses go out the window.
Often, to save myself the headache of grading 50 worksheets in one night, I will just give my students completion credit, especially at the beginning of a chapter. At the beginning of the hour, I go through the class and just check that everyone did it, then we would go through it. However, I found it very hard to keep track of who did the assignment and who didn't. Often, I'd have kids coming up to me and saying "but I had it done that day!" which was difficult because, unless I specifically remember seeing an empty page, I'd have to take their word for it.
So, I decided to get a little stamp. When I check for completion credit, if they finished the assignment, they get a little smiley stamp on their paper. That way if I do make an error, they can prove me wrong. No stamp means the student never showed it to me completed. I have yet to have any student try to tell me they handed something in when they didn't.