What makes this difficult? For one it is largely something unexpected that is the downfall. Additionally the costs of the event are not known. Finally even when you think you are covered, it often is not the case.
Medical Bills Driving Most Middle-Class Bankruptcies - Forbes.com:
"In 2007, medical problems and expenses contributed to nearly two-thirds of all bankruptcies in the United States, a jump of nearly 50 percent from 2001, new research has found.
Since the data used in the study were collected prior to the current economic downturn, it's likely that the current rate of medical-related bankruptcies is even higher, said the researchers at Harvard Law School, Harvard Medical School and Ohio University.
They randomly surveyed 2,314 bankruptcy filers in early 2007 and found that 77.9 percent of those bankrupted by medical problems had health insurance at the start of the bankrupting illness, including 60 percent who had private coverage."
That said, I do not even pretend to know the solution.