That's true.This depends also a lot on size of room, speakers distance to listening position etc...i would loose my hearing if i was mixing at 85dB daily in my studio. In my control room 75dB is already...LOUD.
I also learned to limit exposure to 15 minutes on and 20 minutes off, which helps save your hearing.
Turning the mix down to "elevator music" listening levels as a contrast also help retain a set of mix perspective.
If you hear a lot of reverb at elevator music listening level, you better be mixing surf music, post rock, or ambient stuff. If you hear one instrument dominate the mix at that level, it probably is out of balance with the rest of the mix.