I love this idea. One time I was going to make up little cards of some guidelines I keep in my pocket that I refer to frequently and seem to never keep in memory no matter how many times I memorize them for class. I require that my students memorize them and it has become kind a point to smile about me out of class. So I do it if they have tropuble remembering like me and also to think of me after graduation.
I also think the emails now and then can be good refreshers later when things tend to be forgotten.
