This thesis is comprised of three essays. The first two investigate the relationship between households per capita income and sectoral expenditure shares both in times series and in cross-section in the postwar US. The first uses a partial approach to estimate the rise of consumption (income) dispersion and income effects in the US from 1980 to 2010. We show that income effects are heterogeneous across households grouped by income quintiles and then consumption dispersion correlates the two main driving forces of structural change (price and income effects) in accounting for the magnitude of structural change in the shares of consumption expenditure in the US over this period. The second extends a canonical Bewley-Aiyagari model in continuous time embedded with a two-sector environment to depict quantitatively three empirical regularities in the postwar US (relative price of goods falls and expenditure shares of goods falls systematically with per capita income, both in times series and in cross-section) without departing from benchmark Stone-Geary preferences. We assess the importance of changes in income and relative prices for structural change in the shares of consumption expenditure in the postwar US and conclude they are nearly equivalent forces. We reinforce that reconciling these three main empirical regularities in the postwar US calls for a growth theory that accommodates long-run demand and supply drivers of structural change. Finally, the third essay uses a unique panel dataset with individual-level administrative records of credit transactions, program benefits, individual demographics and features of labor contracts to study how consumers respond to a liquidity shock arising from withdrawals releases from inactive accounts of the Guarantee Fund for Time of Service (FGTS) in Brazil in 2017. Using a difference-in-differences identification design, we find consumption rose and total debt declined after the announcement: during up to twelve subsequent months, for each USD 1 of program benefit, consumers on average increased consumption spending by USD 0.53 - 25 percent of which occurs during the announcement window - and total debt declined by USD 0.07, specially in payroll debt. Consumption response occurred mostly via credit card spending, but evidence of debt-financed durables was also found. Indebted consumers used short-term liquidity in debt modalities (overdraft debt and credit card debt) in addition to credit card spending to smooth consumption. Constrained consumers, measured as young or old, showed stronger consumption responses.