Many patients demand tests, and often doctors encourage them. How much excess care is being carried out is debatable, but some studies indicate that nearly 30 percent of U.S. healthcare expenditures are unnecessary. That would be $700 billion of waste each year. Choosing Wisely, a new campaign supported by several professional medical societies and consumer groups, is encouraging doctors and patients to kick this habit—to curb the overuse of tests and procedures, including the prescription of antibiotics and imaging studies for sinusitis within the first seven days of symptoms.