Because the United States is largely a consumer spending based economy, keeping an eye on spending habits is integral to the understanding and predicting future trends and economic growth. Economists need to know who buys what, how much they spend, and when in their life they spend their money. They cross reference this data with the demographic makeup of the country to get a better idea of which direction the economy is headed.
As you can see above that data shows that spending on all products and services tend to taper off after American’s forty-fifth birthday, housing and healthcare being the only two exceptions, which bodes poorly for everyone who isn’t a nurse or a real estate agent. With a large number of American baby-boomers headed into retirement, their reluctance to spend on common goods and services can act as a bit of a drag on a consumer based economy, but, on the other hand, adds certainty to the very important housing market and health care industries.