i have a pair of plantronic they have worked fine on my iphone 4s since i purchased them. i recieved my new iphone 5s after goingthrough the usual set up they just don,t work

Did you restore your 5s from an older iPhone? If so, make sure you remove the headphones from the iPhone and turn off Bluetooth. Put the plantronic into discovery/pairing mode. Then turn on Bluetooth on the phone. It should pair at that time.

I have the same problem with Plantronics headset. It used to work fine with iPhone 4S and now I have iPhone 6 and I have to pair it every time if I switch off either headset or bluetooth connection on iPhone 6