I just set  my interface's volume knob at a volume that's slightly above activating both speakers.

If i really want to see how it sounds at even lower volume, i pop in dim mode on my interface's software (the thing that control my ASIO settings or w/e) and i just crank the volume to where it's loud to hear, but at a much lower volume than if i were to have dim mode off.

another practice is pick the most quietest time of day, and do some mixing then. Couple the quiet with the decreased volume, and it'll be a different perception entirely.

I also do this technique to ensure that i still achieve my peaks at 0db, but i can save my ears and make decisions the longer i get into it.

I've also started adopting a realization for taking breaks. I just can't do the same rigor that i could do when i first started. besides, it gets not fun at that point.

When I was doing some recordings with Gordon Raphael, he said that the mix should sound good at the quietest of levels. The quietest you can get. Might be an exaggeration, but i applied what he said, and it helped me understand how much of an impact it makes at louder levels.