In a time during which uncertainty prevails – instead of assurances that a universe of options will remain stable throughout a multi-year period – it's generally best to plan for one of the likely possibilities but remain flexible and ready to change when more reliable tenets emerge.

Testy lawmakers and President Barack Obama headed back for a fifth day of debt-limit negotiations Thursday, pointing fingers at each other while trying to stave off a government financial default.

Though sweeping regulations helped to clarify many points about the framework needed for state-based health insurance exchanges, experts at actuarial and consulting firm Milliman say there are important questions that still need answers.