Packaging influences usage behavior long after it has influenced purch
ase. Managers of consumer packaged goods and public policy officials h
ave, therefore, questioned whether a package's size influences usage v
olume. Although often assumed, it has never been supported. Four labor
atory studies and a final study in a Laundromat identity circumstances
in which larger package sizes encourage greater use than do smaller p
ackage sizes. Unit cost is a key factor mediating this relationship. A
fter noting useful implications for decisions regarding package size p
ortfolios, sales promotions, and public policy, the author concludes b
y identifying other important but overlooked factors that increase usa
ge volume and provide research opportunities.