Extended Warranty for tow vehicle?

The base engine warranty on a 6.7L diesel is five years or 100,000 miles. The emissions warranty is 5 years or 50,000 miles. I would recommend you review what is covered in the base vehicle warranty before purchasing an extended service plan. How many miles a year do you put on your vehicles and how long do you plan on keeping this truck? I never purchase extended service plans on anything and figure the money I save will pay for a major repair if I ever need to have a major repair done.