At first glance, Rick Hill and Lauren Dragon seem to have little in common. Hill, 60, has worked for the past decade as a high-paid software engineer, much of the time for Fidelity Investments. He and his wife, who works in marketing and communications, are empty-nesters who own a condo in Boston’s trendy South End, where they enjoy the bustling restaurant scene when not indulging their taste for travel. Dragon, who lives in Haverhill, spends her days assembling circuit boards for $10.45 per hour at Celestica, a multinational contract manufacturer that operates a plant just over the border in Salem, NH. The 48-year-old single mother struggles to cover the rent on the house she shares with two of her four children and worries about getting sick, having been without health insurance coverage for four years.