Dynamic defaults for recurring purchases determine what happens to consumers enrolled in a product or service who take no action at a decision point. Consumers may face automatic renewal, automatic switching, or non-purchase defaults. Privately optimal dynamic defaults depend on the contributions of adjustment costs versus psychological factors leading to inaction: both produce inertia under renewal defaults, but differ under non-renewal defaults. Defaults have equilibrium effects on pricing by changing the elasticity of repeat demand. Socially optimal defaults depend on firms’ pricing responses as well; more elastic repeat demand restrains price increases on repeat customers and can reduce inefficient switching.
See also discussion in The Incidental Economist.