AVETT BROTHERS AT GREENSBORO COLISEUM: Remember when the Avett Brothers used to celebrate every New Year’s Eve at the modest Neighborhood Theatre? I’m not sure they do, either. Thankfully, Greensboro’s just a short drive away. The Concord-based band is currently riding high on a Best Americana Album Grammy nomination for its latest release, The Carpenter. The album’s dark undertones center on love and loss, but it doesn’t overwhelm the band’s energetic, back-porch spirit, which has remained tried and true after all these years. And with experience comes experimentation — expect to see a few more electric guitars on stage these days (and a few more members, as the band has added a touring drummer and keyboardist). And expect a rollicking NYE — these guys have that down to a science at this point. With Amos Lee.