This is a limiting structure, as real-world events occur in continuous time, and more importantly, some decisions/transitions are joint, or occur together. The model also has no labour-supply dimension. There are models for labour-force participation, unemployment and retirement but no model of hours worked and the variables that influence those hours, including the family budget, tax rates, and health. Changes in the macro economy can be entered into the model as a scenario, however, there is no general equilibrium mechanism within the model itself.