Always on the road for me, not off road. That said I also don’t bother in London, there’s people to talk to, and I don’t want to give fodder to the car driver who will inevitably knock me off at some point.
The hand wringing on this is daft, this:
Or rather, there are risks but not ones you can mitigate by not wearing headphones.
sums it up nicely IMO. I don’t feel any more or less safe with headphones. The reduced wind noise means I tend to hear ‘phantom cars’ less than when I’m not wearing headphones, and I also was entirely unable to tell the difference between the engine note of the car that clipped my bars.
In fact, the vehicles which bother me most are motorbikes you can hear coming (above headphones) for ages before they streak past, generally leaving plenty of space. Cars that come far too close tend to sound like every other!