This brief first provides more conceptual details about how a life-course approach can be adapted to track inequalities in financial hardship due to out-of-pocket health spending by using the age structure of a household. Recognizing that the household is the risk-pooling unit that copes with the cost of needed health care, the life-course approach can be applied to the age structure of the household to distinguish between six distinct and mutually exclusive household types: very young (all members aged ≤19 years), younger (all members aged ≤60 years, with at least one member aged 0–19 and one aged 20–59), adults only (all members aged 20–59), multigenerational (at least one member in each of the following age groups 0–19, 20–59 and ≥60 years), older (all members aged ≥20, with at least one member aged 20–59 and one ≥60) and only older (all members aged ≥60). Two separate indicators of financial hardship are used: the population with catastrophic out-of-pocket health spending and the population with impoverishing out-of-pocket health spending.