What decibel level do you listen at? What is ideal?

I have a phone app and an old Radio Shack Db meter. The Radio Shack seems to register higher. I usually land somewhere around 80dB +/- 5 Db. like @mulveling stated there is a point where the music comes alive. Sometimes that is more like 85 Db for me. And as resolution of the rig has improved lower levels can be pleasing too. BUT sometimes the music just needs to breath. I don’t drink alcohol when I listen to prevent stupidity with loudness. Age 70 with hearing aides. 

For me my listening levels vary all over the place, when I am listening late at night which I often do, levels are very low probably no more than 60-65 dbA. During the day, when there is not a concern about disturbing anyone, those levels can have 100 dbA peaks, though I never listen at those high levels for very long. Long term levels at loud volumes 80-90 dbA but even that is not continuous. Already sporting measurable hearing loss, I am trying not to make it any worse than it already is. That said, when I am practicing trombone, which I do almost daily, the SPL easily exceeds 100 db and while it is possible to reduce the level a little bit, its not easy to play much quieter than that.

For a free and immediately useful sound level meter please consider downloading one to your smartphone from the National Institute of Occupational Safety and Health. 

Simply go to your phone's App Store and search for:  sound level meter. There might be a number of options, but the NIOSH app is simple and can be trusted. 

Is this as good as a calibrated studio level device? No. But it's good enough to get a useable level reading to set a baseline or observation. 

When the wife is at home, 60-70. When she is gone, +80 🤣

I have no idea what decibel level I listen to music at. I simply adjust the volume to be suitable to how I feel at that moment and what genre of music I am listening to at the time.