Heidi Steffen and her husband used to treat themselves most weeks to steak at Sodak Shores, a restaurant overlooking a lake near their hometown of Milbank, S.D. Then they each got an iPhone, and the rib-eyes started making fewer appearances. “Every weekend, we’d do something,” said Ms. Steffen, a registered nurse whose husband works at a tire shop. “Now maybe once every month or two, we get out.” More than half of all U.S. cellphone owners carry a device like the iPhone, a shift that has unsettled household budgets across the country. Read the full story at The Wall Street Journal.