What DB level is best for judging audio equipment?

It varies from recording to recording , No magic number.

Ever since I swapped the Joseph’s for the Maggie’s I have found myself playing music a good 5db or more less than previous.
The Maggie’s just seem to reveal so much more detail without having to push them.
Now that is not saying they do not play loud,more that I do not really feel the need to play loud much lately.

So mid 70 to 80 dB is about it right now.

Peaks of low-to-mid 80s most of the time. Anything above that would be for a single song only that needs to be cranked ;).