We have entered the age of simultaneity. Once upon a time, not too long ago, in fact, retro looks had their day in the sun and then faded again, replaced by the next old idea newly exhumed from the thrift shops. No more: Looks for spring and fall range across a vast spectrum of inspiration, with the ‘20s, the ‘30s, the ‘40s, the ‘60s, the ‘70s, and pretty much every formerly degraded look from the ‘80s represented, somewhere. The really postmodern thing is go time-traveling in your closet, mixing and matching among the epochs. Straight-up homage would be so…predictable.