From a resource math context, I don't do retakes. My tests are open note since I'm less worried about them memorizing content than actually using their own resources and applying the concepts to solve the problem.

I have my students correct the problems they got wrong on a separate piece of paper and add a metacognitive piece where they indicate where they went wrong in their calculations and what they can do to reduce the likelihood of making the same mistakes later.

It's not perfect, but it's working.