Every tire manufacturer stands behind their product in the form of a warranty. Typically speaking, they will repair or replace aftermarket tires that show defects that result from faulty materials or workmanship. The warranty outlines the time period in which they are willing to do so, and it usually lasts four to six years after the original purchase date. This is why you should always file away that receipt—just in case.
Make note that if your tire's original tread wears down to 2/32" before that time period is up, the warranty will be voided. And speaking of tread, many tire manufacturers offer treadlife/mileage warranties to further entice you to make a purchase over the competition. Not to discredit a warranty like that, but road conditions play heavily on tread wear so not all consumers will reach the warranted mileage.
For more information, we suggest you read about tire warranties in our library of Tire Tech articles. Or, you can contact one of our sales specialists. They'd be happy to walk you through any applicable warranties associated with your tires.