GMC Repair: Headlight sockets 2003 Envoy, fuse box, oem replacement

Question
I have a 2003 Envoy and the headlight sockets keep burning out.  The dealer replaces them at a fee but says there is no problem.  This happens with both sides.  Why do the sockets burn out?  I can see the burned and melted plastic in the sockets.  The car has 99k miles on it.

Answer
Hi
My guess, without seeing vehicle, is wrong bulbs. If there is too much current flow, it will get too hot. Maybe it has HID bulbs? Or a non OEM replacement bulb (colored?)
The only other item would be to check the grounds for the sockets. These systems use a "module" which is basically a relay in the underhood fuse box. There MAY be a problem with that, but the current is too high.
I hope this helps
Pawl