People without health insurance don't get enough preventive care — simple but important things like vaccinations and blood tests.
But surely having insurance every now and then is better than none at all, because people can get caught up on their tests when they are covered, right?
That's a widely held view, and one that would be good news to the millions of people who go on and off health insurance each year. Some of them are losing or changing jobs. Others slide on and off Medicaid as they take on temporary work, marry or divorce.