When you're considering battery life, expect to see a wide range. Depending on the manufacturer, advertised talk times for mono headsets start at about 4 hours and go up to 9 hours. Standby times start at about 100 hours and extend to about 250 hours. For speakerphones, talk times start at about 14 hours and extend to about 20 hours; standby times start at about 300 hours and go up to a whopping 800 hours. With solar-powered speakerphones, theoretically, you can hope for unlimited talk and standby times, as long as your device can soak up lots of sunlight daily.

In a perfect world for headset makers, people's ears would be identical. They aren't, of course, and that's why we prefer that headset bundles include multiple options to help you find a good fit. Some manufacturers are generous with their goodies, providing small, medium, and large earbuds, along with an additional earhook or two. Others give you an AC charger and a user guide, but nothing else in the box.

As of this writing, the most current Bluetooth specification is . This promises more-frugal power consumption. "Low energy is the hallmark feature of this specification," says Michael Foley, executive director of the .

The previous version, , allowed the Bluetooth protocol to piggyback on 802.11 Wi-Fi when you needed to take care of more-demanding tasks such as sending video from your camera to your TV.