NEW YORK — The summer hiatus allows many habitués of the art world to escape for vacation, and to absolve themselves of art world responsibilities. The endemic fear of ‘missing out’ is allayed for a few short weeks. This comes to an abrupt halt at the end of the Labor Day weekend in early September, which marks the beginning of the Fall art season. Experienced by many in the art world as a ‘back to school’ moment, friends and colleagues reconvene at innumerable openings, dinners and drinks to celebrate new exhibitions and get up to date on recent gossip. While the heavy schedule of events can appear daunting, the flood of new art and ideas makes the effort well worthwhile.