The authors examine factors that affect product-usage compliance, or the act of using a product as it is intended to be used. They develop a conceptual model of compliant behavior as a function of four main constructs: (1) salience/mindfulness, (2) the consumer's costs and benefits of compliant behavior, (3) advertising and distribution cues to action, and (4) the perceived threats associated with noncompliant behavior. They test the model using a regression mixture model of compliant behavior calibrated on unique panel data from four categories of pharmaceutical drugs that are used to treat chronic (i.e., lifelong) ailments. The findings include insights into the dynamics of product compliance: The data support the proposed four-stage evolution of compliant behavior between consecutive service provider (e.g., doctor) interventions. For marketers, the authors find substantial heterogeneity across consumers for the effects of cues from advertising and distribution. For example, in some segments, advertising has a positive impact on compliance (directly and/or by heightening responsiveness to product-efficacy evaluations), whereas in other segments, its effect is negative. Thus, the authors shed new light on the effects of advertising, which has both strong advocates and opponents in the pharmaceutical industry.