Y'know, rarely do I buy the "extended warranty" that most places try to peddle on you nowadays. If you buy the item from a reputable manufacturer, it should be unnecessary.
In the case of tires, I have to make an exception.
You can control the quality of tires you buy and put on your car, but not the quality of construction workers who don't know how to secure their nails, screws and bolts for travel on highways, streets and other local thoroughfares. They're a nefarious bunch for the most part. I'm not for extra taxes, but I'm contacting my local elected officials to institute a tax on all businesses who transport these little metal devils on the streets we drive...and stiff penalties/massive fines if they get caught dropping a load of these on the highway.
For the second time in a year, one of my tires caught one of the little buggers -- this last one was not a nail or screw, mind you, but a BOLT. I pulled my receipts from the glove compartment, used Yelp to find the nearest Discount Tire, and called for a tow.
The replacement certificates I got were $16 per tire (back in NC, but they're good here too), and worth every penny. The folks at this Discount Tire location were extremely nice, and had me in and out of there in about 30 minutes (with no appointment). There is even free water for customers. They were able to fix the tire instead of replacing it, which is fine (as long as it holds).
Every Discount Tire location I've visited has been great as far as the transparency of what you're getting, the quality of customer service, and the wait. In a town of 4.3 million people and never-ending road construction, I have to recommend the free replacement warranty on your tires, no matter where you buy them. I prefer getting mine from DT.