Bluetooth headphones have exploded in popularity, with the market continuing to grow each year. The category, which includes over-ear headphones like the Sony WH-1000XM6 and in-ear devices like Apple’s AirPods line, offers a mix of comfort and convenience, and we’ve reached a point where it’s hard to find name-brand headphones that don’t sound at least somewhat decent. But while most marketing for consumer-grade wireless headphones focuses on headline features like active noise canceling, there’s another feature most people should add to their list of non-negotiables.

Once upon a time, during the halcyon days of the ubiquitous headphone jack, swapping between devices was a matter of popping the plug out of one and into the other. Maybe you’d get an audio splitter if you really needed to use two audio sources at once, but that was as complicated as things usually got. With Bluetooth, simply switching even the best wireless headphones over to another device involves fiddling with settings menus and dealing with frustrating connection issues.

Finicky connections are a defining trait of the decades-old Bluetooth protocol, and although improvements continue to be made with each generational update, that essential character remains. That’s where Bluetooth multipoint comes in. It’s a feature that allows a Bluetooth device to remain connected to multiple devices at once, swapping between audio streams from each as you use them. While multipoint can introduce some annoyances of its own, it’s still far preferable to manually switching between devices over Bluetooth. Here’s why it’s a must-have for most headphone shoppers.

Bluetooth multipoint is a manufacturer-introduced technology which can allow for a wireless audio device to maintain a connection to multiple audio sources. It usually allows for a connection to two devices, though there are exceptions. The feature is more common on high-end consumer headphones like the Sony WH-1000XM6, though it can sometimes be found on downrange products.

Your Bluetooth devices use different Bluetooth profiles for different types of audio. Music and other media streams use the A2DP profile. On certain devices, this can also transmit high-resolution wireless codecs like Qualcomm AptX and Sony LDAC. You may simultaneously use an AVRCP profile to send volume and play/pause commands to the host device. When you get a phone call, you’ll switch over to the lower-quality audio of the bidirectional HFP profile. When you’re listening to music on your laptop, you might get a phone call, and your headphones will prioritize the HFP connection to switch over. However, if you’re using HFP for a Zoom call, it may retain priority until you answer the incoming call.

Not all multipoint is made equal, and whether a particular implementation of it works for you depends on which devices you plan to use the headphones with. It’s a good idea to test the multipoint functionality of a pair of headphones before you buy them, if possible, to ensure that their multipoint implementation works well with your particular devices. If you can’t test that functionality before buying, do so before the return period ends.

Bluetooth multipoint can make it much easier to use multiple devices with a single pair of headphones, but it can also introduce new headaches. Multipoint is not part of the Bluetooth specification, and is instead implemented by device manufacturers on top of the Bluetooth stack. This explains why it remains a relative rarity despite consumer demand. The ability to handle multiple streams was added with Bluetooth 4.0, but multipoint features are logics built atop the Bluetooth protocol. Bluetooth cannot mux or sum together multiple audio streams, so multipoint does not allow a user to listen to audio from multiple devices at once. Instead, it decides which stream should take priority and pipes that to your ears, often pausing other media. Incoming phone calls usually demand precedence, for example.

Multipoint often assumes you’ll only use one device at a time, but try scrolling Instagram on your phone while listening to a podcast on your computer. As Instagram’s annoying autoplay causes the app to output audio, your multipoint headphones will divert away from your podcast. This will often happen even if your phone’s media volume is set to zero. Equally annoying notification dings on your phone may ride along on the same Bluetooth profile as phone calls, interrupting you with every group chat message.

Apple and Samsung have their own solution to this issue. Technically, the best AirPods and Galaxy Buds do have multipoint  — a modified version designed to work exclusively with their own products. While often justifiably perceived as user-hostile, this approach can yield better Bluetooth switching results in normal use because the company controls the way Bluetooth is implemented on its headphones, phones and laptops, whereas companies like Sony or Bose do not have the benefit of bespoke ecosystems.