I do not keep individual files on students, but what I do is have a folder for each student (different colors for each class) that I keep in different crates for each class. Students keep their work in these. I photocopy one sample (not necessarily the best) along with the rubric that I use to grade it and put it in a large, cheap 3 ring binder. I do this for each lesson and each project. That becomes my accountability folder for the year.