I've learned from years in the studio, ears get tired after 10 hours of concentrated listening. The brain gets tired too. You start to make mistakes. Your judgement gets fuzzy. After midnight I find it more difficult to problem-solve and can easily get frustrated. I used to keep recording into the wee hours of the morning, until the inspiration wore out, but now I cut off sessions at 10pm, even if we are on a roll. I know that staying up late will ruin productivity for the following three days. In order to stay on schedule, I'll push everyone to get out of the studio and get some rest.
The session schedule that works for me is from noon to 10pm, with absolutely one day off a week. If you are on a long project, you MUST have that one day a week to rest your ears. Minimum.
I try to record in a way that the song is already pre-formatted by the time we go to mix stage. Decisions are made on panning, placement, stacking, tuning and samples ahead of time. Mixing becomes fairly straightforward at that point. I start a mix around noon, pushing up all the faders on the board to get a quick balance. Just get that stereo buss compressor moving, detail the overall sound with the stereo bus EQ, automate vocal rides and delays and maybe put in a little "slippery fader" to make the choruses jump up. I work quickly, mixing analog on the desk, grabbing several faders and making many moves during a single pass, not laboring over details that don't really matter. Then I shut it all down at 10pm and come in for a fresh listen at noon the next day. That is when I know if the mix is done or if it needs a bit more tweaking.
Moderate listening levels will also keep your ears from getting fatigued. So far 30 years of recording hard music has not produced hearing loss for me, and that is the way I want to keep it.
I rarely listen to music when I am not in the studio, which upsets people who think I should enjoy listening to their home-made recordings.... well, if I'm not working, I'm not listening to music. Music is generally not entertainment for me. It can be enjoyable, but it is serious business in my world.
As far as listening to music outside of the studio, I want to be knowledgable about the latest trends, but not influenced by them if I can help it. I take time to research the buzz bands, but that type of listening is categorized as "work-time" for me. This is not to say that on occasion I don't enjoy driving with "Kid-A" or a Charles Mingus classic in the car.... but for me whenever there is music in the room, my focus is automatically drawn toward it. It is a curse. Even background music in a restaurant. It steals my concentration, makes it difficult to hold a conversation because I'm so busy picking apart the arrangements, melodies and rhythms. Elevator music becomes offensive! "Robot" vocals on country music radio while I'm eating breakfast at the diner is like fingernails on a blackboard! If I listen to music I want to be fully engaged and willing, then I'll let myself be completely absorbed.