Deconstructing Lifecycle Expenditure
Mark Aguiar and Erik Hurst
In this paper we revisit two well-known facts regarding lifecycle expenditures. The first is the familiar “hump” shaped lifecycle profile of nondurable expenditures. We document that the behavior of total nondurables masks surprising heterogeneity in the lifecycle profile of individual sub-components. We find, for example, that while food expenditures decline after middle age, expenditures on entertainment continue to increase throughout the lifecycle. These patterns pose a challenge to familiar lifecycle models that emphasize inter-temporal substitution or movements in income, including standard models of precautionary savings, myopia, and limited commitment. Secondly, we document that the increase in the cross-sectional dispersion of expenditure over the lifecycle is not greater for luxuries. In particular, the dispersion in entertainment expenditure declines relative to food expenditures as households become older, casting further doubt on theories that emphasize (exclusively) shocks to permanent income. We propose and test a Beckerian model that emphasizes intra-temporal substitution between time and expenditures as the opportunity cost of time varies over the lifecycle. We find this alternative model successfully explains the joint behavior of food and entertainment expenditures in the latter half of the lifecycle. The model, however, is less successful in explaining expenditure patterns during the early half of the lifecycle.