New research from Gartner suggests that shipments of PCs, tablets and mobile phones will continue to grow year-on-year through to 2017, with the exception of this year where sales of PCs and tablets will decrease slightly – phones, though, will continue their inexorable march to global ubiquity.

Worldwide combined shipments of devices (PCs, tablets, ultramobiles and mobile phones) are expected to reach 2.5 billion units in 2015, a 1.5 per cent increase from 2014, although it is down from the previous quarter's forecast of 2.8 per cent growth. End-user spending on devices will total $606 billion in 2015 and will show, for the first time since 2010, a 5.7 per cent decline in current US dollar value – although it will then rise in following years.

"Our forecast for unit shipment growth for all devices in 2015 has dropped by 1.3 percentage points from last quarter's estimate," explained Ranjit Atwal, research director at Gartner, "partly due to a continued slowdown in PC purchases in Western Europe, Russia and Japan in particular, largely due to price increases resulting from local currency devaluation against the dollar."

The only market that continues to show growth is the mobile phone market where, in contrast, prices continue to fall. Gartner says the emerging markets are driving the smartphone market upward, with China still leading the way.

Global shipments of mobile phones in 2014 amounted to 1.88bn units, and will climb to an estimated 1.94bn this year, reaching 2.06bn by 2017. Ultramobile shipments (tablets and clamshells) amounted to 226m units, and will drop to an estimated 214m this year, before bouncing back to 244m by 2017. Of the 214m ultramobile units in 2015, tablets will account for 207m, a decline of 5.9 per cent from 2014.

"The tablet market is hit by fewer new buyers, extended life cycles and little innovation to encourage new purchases," said Roberta Cozza, research director at Gartner. "At the same time, the value of a smartwatch for the average user is still not compelling enough and the impact of these wearables on tablet purchases remains negligible. The tablet has become a ‘nice to have’ device, and there is no real need for an upgrade as regularly as for the phone."

Tablet sales are also being impacted by the growth in popularity of phablets and screen sizes of 5-inches or more, plus more reliance by users on their smartphones as functionality increases. Gartner says this is affecting the appeal of smaller tablets in markets such as Western Europe and North America, and as a result, Gartner has extended the average lifetime of the tablet to three years by 2016. It also expects the tablet market to reach a penetration close to 50 per cent of households in mature markets by 2016.

Meanwhile, the ever-reliable mobile phone market is expected to show decreased growth, down to 3.3 per cent growth in 2015.

"The global market has been affected by a weaker performance in China,” said Annette Zimmermann, research director at Gartner. “We have witnessed fewer and fewer first time buyers in China, a sign that the mobile phone market in there is reaching saturation. Vendors in China will have to win replacement buyers and improve the appeal of their premium offerings to attract upgrades, if they want to maintain or increase their market share.”

However, the opportunity for double-digit smartphone growth still exists in emerging markets outside of China, so long as vendors can quickly enhance their expansion into these territories.