Regenerating Material Instanced Dynamic

I made a blueprint similar to the sample in the documentation.

Question, If I were to hook up a Creation of DynamicMIC into the construction script.
This means that a new MID is generated every time the construction script runs. Wouldn’t this mean that a new MID is generated everytime? Does the Old one gets deleted. I tried debugging the name of the created MID and apparently they’re all different name. I’m a little concerned if these MID stays in the memory or if they get deleted.