Is headphone listening a primary or backup for you when listening to music?

I use headphones if I am on my personal desktop working on personal stuff and if I want to sample music before purchasing or adding to the Spotify library. I also extensively use headphones/earbuds while I go on long walks.

High end headphones 90% of the time. And I actually have treated room and room correction. Still does not sound as good as in planar cans.

I have a dedicated desktop headphone HiFi system, but I do keep a high quality headphone system integrated into my main speaker system that I use purely for diagnostic purposes and providing a different perspective of reference when making changes at or near the source. This can be very useful.

I got back i to phones when got divorced.   I packed up all of my gear,  put it in storage and got a decent headphone set up.  

That was 5 or 6 years ago but I still use it occasionally.     

I use it when it's late also.  Great way to listen without bothering others.