Hello.

Just wanted to drop this knowledge here so someone else can have it.
I run the IT sector of a company and we own ~60 of these headsets plantronics poly Blackwire C3220 (Now HP).

Quality is good, but the planned obsolescence is evident.

They last, on average, 2 to 3 years.

The cable is awful, if the end-user is next to the window and the sun hits the cable, after a while, the cable starts to peel off the rubber coating, exposing the wires and breaking. Also, the padding on the ears is not very good, some users are OK and others have their ears hurting after a while. It also has a poor quality material so it will start to disintegrate, so be sure to get some replacement pads.

The repairability is close to zero, it's all using a very thin copper cable. It's not zero because you can at least open it with a special screwdriver and see that it's not repairable.

Hope it helps.