Consumer spending is the engine of the U.S. economy, accounting for roughly two-thirds of overall economic activity. In theory, when consumers feel financially secure and optimistic, they tend to spend more, driving corporate profits and economic growth. When they feel uncertain, they may tighten their belts. In reality, how consumers behave depends on many factors, especially because not all consumers are alike. For this reason, having a holistic understanding of the financial health of consumers is one of the most important ways for long-term investors to make sense of the current environment.