I’ve never actually run any of the old modules like Keep on the Borderlands or anything like that. I’m much more used to homebrewing a setting entirely or at most grabbing a few elements from a published adventure (I took a bunch from Willow, for example). I think this is why most of my favorite systems tend to be more in the NSR camp; I just never end up needing compatibility with older material.
Is running retro adventures in their entirety the most common practice for OSR tables? Or is the homebrew approach how most people are doing it?
I use them more as a general outline or idea. The Mystara Adventure Crown of Ancient Glory is a good one to mess with as is Queen of the Demonweb pit for AD&D. The older the module the more it is just guidelines. Palace of the Vampire Princess is a great one that the GM/DM will have to do a lot of work on.