This is convenient for the student and for me. If we do not finish a lab I can have the kids store their work in there. If I need to go to a parent-teacher meeting I can pull their work to bring with me. I can also pull a piece of student work to use an example for another student to see.
If I want to return work without passing papers back during class time, I can have an assistant file the assignments.
These is a good alternative to the trash can. One school I was at had PORTFOLIO DAY. Keeping the folders allowed kids to have access to their previous work.
In the past I have had students keep a log of their scores and grades in their folders and we update every two weeks.
Hope this helps,
Love to Teach and Teach with Passion
Remember...It's not Magic, It's Science