Loading music on the Apple Watch is as easy as a couple of taps. But listening to those songs? That's another matter entirely. Since the Apple Watch doesn't have a headphone jack, owners of the smartwatch will need to pick up a pair of Bluetooth headphones.

“Having a wire makes things less convenient than having Bluetooth connectivity,” said Angela McIntyre, Gartner's wearables research director. While much of the audio industry has left the cord behind, headphones -- even high-end ones -- are still stubbornly tethered. But the Apple Watch could spur the move to cordless. 

Whether it’s Apple's Beats, JayBirds, or even a cheap $30 pair found online, there are a growing number of headsets to choose from. And it’s a market the Apple Watch could jump-start as owners look to listen to music -- while out for a jog, say -- without dragging their iPhone along or the mess of cords that typically comes with it. McIntyre noted that many smartphone users with tethered headsets will strap their device to their upper arm as a workaround. "It’s even less convenient to do with a device on a wrist,” she said.

While wireless headphones have yet to take over the market, consumer demand for them is expected to increase in the coming years. In 2014, worldwide shipments of all types of headphones grew by 8.5 percent to 309.5 million units, for revenues of $9.4 billion. In-ear headphones accounted for 60 percent of the market. During that time, manufacturers, such as Sony and Beats, also began introducing or adding more Bluetooth earbuds and headphones to their lineup. By 2018, that segment is expected to account for 21 percent of shipments, market researcher FutureSource Consulting says.

“The demand for headphones is increasing, especially as consumers are using their mobile devices for a plethora of content on the go, whether that’s whilst commuting to work, running, cycling, or simply walking into town,” Simon Bryant, associate director of consumer electronics for FutureSource, said in a statement.

In response, manufacturers have offered sport versions of their headphones, such as Jaybird’s Bluebuds X, LG's Tone and Jabra’s Sport Wireless+ set, which are designed to be sweatproof and weatherproof. But as smartwatches become more advanced, headphones will add features that go beyond the sports enthusiast market.

“The convenience factor that smartwatches have certainly could spur the use of Bluetooth headsets especially as the use case evolves,” McIntyre said. If you're planning on listening to music on your Apple Watch, here are a few options to choose from: