how long to retain records of a terminated living will in michigan

I am sorry, but I do not understand the question. As I understand it, a "living will" is nothing more than a written set of desires a person has about how much he or she wants medical professionals to work to prolong their life. These are not legally effective in Michigan, and I have no idea why one would need to retain one of these that had been terminated. If you mean that the person has died, I guess I would hand onto it for a while, but I am not sure what the use would be. Sorry.