I have an LG 4G-LTE phone and a Plantronics Voyager Pro headset. It seems to me that once the two are paired I should be able to turn the headset on and off without disturbing things, but it is not so.
To use the headset after I turn it off, I must:
1. Turn the headset on in pairing mode.
2. Go to the phone's Bluietooth menu.
3. Unpair the headset.
4. Turn the phone's Bluetooth off.
5. Turn the phone's Bluetooth back on.
6. Pair the headset again.
If I don't perform every one of these steps, the phone says it's paired with the headset, but ignores it, using its own speaker and microphone instead.
The same applies if I take the phone out of range of the headset and then bring it back.