Ok - so a lot of the time, i would import a tree, proxy it, then edit its materials and save it into a central location (ie - C:/corona proxies)
Down the track, when i am doing another project months later, i might possible import the same tree again, proxy it and if its in the corona proxies folder and it asks me that it already exists, then i know that ive already done the materiality on it so therefore i would like to use the existing proxy if that makes sense. Does that make sense?