Another note about ear fatigue to follow up on the good advice here:Lots of good advice in this thread.
Ear fatigue is real. So is brain fatigue. I did a marathon session a couple years ago tracking 15 or 16 songs, 1 or 2 takes each. Then, I helped mix the tunes that same day. When I listened back with fresh ears the next day, the first songs to be mixed sounded pretty good. All the "later" mixes were super harsh with way too much high end. Why? Because of ear fatigue. We couldn't "hear" the highs because of exhaustion deafness.
You aren't doing yourself or your band any favors at all. Send in the first 2-3 takes and get feedback. Most likely, everybody will be thrilled with them.
Listening at lower levels than what’s “fun” or more pleasing will extend how long you can go before ear fatigue sets in. I was offered the advice by more than one professional mixer who said that keeping the speakers at moderate conversation level achieves this. It results in a better mix, to boot. The level shouldn’t change much, and when it does it shouldn’t be for long, and it should go back to the reference level.
I don’t imagine this will hold up through an entire day of recording and mixing, but it should allow for better results without burning the candle at both ends in the same long day.