In terms of pedagogy, review is such an important aspect in the learning process. This video outlines progressive review and how we use it in our group lessons.
I don't believe in review for review's sake.
Each time we ask a student to review a piece it should be with a purpose in mind. Either to work on a particular technique such as achieving a type of articulation, or because that piece helps the student with a technique that they are going to learn in a new piece. The fact that students already know the piece, means they are taking on the learning point with so much more success and are able to implement it much more easily.
Hope you enjoy the video!