An overhead inspection is performed, the pole is hammer sounded, bored and the dirt is removed from around the pole to a depth of 18 inches. A pesticide may be added to the inside of the pole. External decay is removed and a preservative is applied to the outside of the pole and then it is wrapped and the hole filled and stamped.
If anything was to cause the inspector to reject a pole (split top, rotten butt or a hollow heart) it would be recorded with all the information available including a GPS position and address. The pole would be marked and the client notified.
An annual ground line inspection is the best way to maintain a healthy overhead system and extend the life of the poles.