When a couple bought this 1,171-square-foot Upper West Side apartment in 2012 and moved in with their two toddlers, they weren’t in love with its looks. “It wasn’t beautiful, but the layout was pretty perfect for us at the time,” one homeowner says—and they were particularly fond of one amenity. “We had had laundry in the basement before, and now we have a full-size laundry room. It seems like a silly thing, but I thought that was amazing.”