In my classroom, I allow the opportunity for students to retest on a concept or redo an assignment to gain points back. I felt like students were abusing the right to redo, and instead weren't putting effort into their work the first time around.
I created this Request to Retest in order for students to prove they have studied and have completed the work needed to improve their scores. Students are required to turn in what they studied/how they studied. If they studied with another student in study hall, I asked that the study hall teacher sign off on that. The bottom of the form requires a student, parent and teacher signature which helps all of those involved to know what the student is doing.
Edit this form to the needs of your classroom.