I use a prize incentive program to keep my students motivated to practice. For every 15 minute plus practice session, the student receives one point toward a prize of their choice. 5 points for a piece of gum, 25 for a stuffed animal, 100 for a hardback book, etc. Nothing new, my piano instructors did the same type of thing. Usually either the student (me) or teacher (well, this is me know and folks not much has changed) would lose track of the points and both parties would end up frustrated.
Enter the easy wipe-off bar graph.
I took an old picture frame and stuck in a customizable bar graph. Cleaned the glass, and grabbed the dry erase markers. That's it.