It's time to kiss the tablet boom goodbye, as shipments of the once-dominant Apple iPad decline amid a worldwide slowdown for the devices.

Shipments of all tablets worldwide will increase by just 7.2 percent this year, compared to 52.5 percent in 2013, according to a projection from research firm IDC. Tablet shipments this year will total 235.7 million.

The numbers reflect widespread reliance on PCs and smartphones for computing and communicating. Buying trends show that consumers and businesses still look to run full-fledged applications on PCs, which have experienced a jump in sales recently.

Otherwise, users are hanging on to tablets longer than expected, which is one reason for the slowdown in tablet shipments, IDC said. Tablet refreshes were expected every two to three years, but owners are holding on to devices for three years and longer, IDC said. New software can run on old devices, and there is no compelling reason for tablet owners to upgrade, IDC said.

IDC's numbers include hybrid devices that are mainly tablets, but can also be laptops when needed with keyboard attachments. The increase of shipments of such devices, which mostly run Windows 8, was just 4 percent.

IDC is projecting shipments of Apple's iPad to be 64.7 million units this year, a decline of 12.7 percent compared to 2013. Apple has reported declines in iPad shipments in recent quarters, but iPhone and Mac shipments increased in the most recent, October fiscal quarter.