Much analysis in macroeconomics empirically addresses economy-wide incentives behind consumer/investment choices by using insights from the way a single representative household would behave. Heterogeneity at the micro level can jeopardize attempts to back up the representative consumer construct with microfoundations. One complex aspect of micro-level heterogeneity is household size, as individuals living in multi-member households have the potential to share goods within the household, benefiting from household-size economies. Theoretically, we show that validating the role of a representative consumer would require that the way individuals benefit from intra-household sharing is strictly aligned across the rich and the poor: once expenditures for subsistence needs are subtracted from disposable household income, household-size economies the remainder (discretionary) household incomes entail must be the same across the rich and the poor. We have designed a survey method that allows the testing of this stringent property of intra-household sharing and find that it holds.