That wonderful layer of leaves piled on the sidewalks is so charming that it's easy to forget what comes next. We might not want to think about it, but after the leaves fall, so do renter’s moving ambitions--it seems that nothing could possibly be worse than packing a U-Haul in the snow. But for NYC dwellers, there are some strong reasons to go searching during the winter months of November to February, when the Manhattan real-estate market slows down and is on the cusp of change. From couples to discretionary movers to higher-earning business professionals, now is the opportunity for Manhattanites to shop for NYC rentals.