One indication if your area has detailed Bing map data already or not is by finding where you are curious about and then seeing if right mouse clicking that the ‘View bird’s eye’ selection is possible or not. That’s the 4-way aerial photo data, that I think might be used for the really detailed areas in 2020.
Bing Maps - Directions, trip planning, traffic cameras & more
You don’t need to get too far out of a major area for it not to be there. I wonder if this will be the limits where the autogen takes over a lot more?