The one D&D game I've played in so far was homebrew. It looks like the next campaign I play in will be homebrew modeled in some ways after a setting.
If I ever run, it will probably be homebrew, unless I have a specific idea for a setting that's particularly non-generic (such as Eberron or Darksun).
When I ran a vamp game in Chronicles of Darkness, I was careful to make sure the half of my players who've played World of Darkness games knew that I didn't really know how mages, werewolves etc. ran in either current or past versions of the setting and rules, and that mine would not necessarily work that way.
Which brings me to what I really want to say. Please, as a DM, don't assume all your players are familiar with a setting without checking. And as a player, listen to your GM about what carries over from canon and what doesn't. I know that's much more complicated in D&D, with multiple settings and a far wider range of info... but some of us are new to D&D. We wanted to be playing (and occasionally running) all along but didn't have the chance, so don't assume we know what the more fortunate and experienced might.