What happens when every person on the planet has a cell phone (or two)? Sales are going to decline. What phone are you using right now? How often do you upgrade? Gartner, Inc. said global smartphone sales will continue to slow and will no longer grow in double digits. Worldwide smartphone sales are expected to grow 7 percent in 2016 to reach 1.5 billion units. This is down from 14.4 percent growth in 2015. In 2020, smartphone sales are on pace to total 1.9 billion units. "The smartphone market will no longer grow at the levels it has reached over the last seven years," said Roberta Cozza, research director at Gartner. "Smartphone sales recorded their highest growth in 2010, reaching 73 percent."