13,500 miles on car/tires. Replace 1 or two tires after sidewall flat?

Like the title says, one of my tires has a puncture too close to the side wall, but I've barely got over 13,000 miles on the car and tires.I'm inclined to replace two tires, but was wondering if only one would be OK at this mileage.Thanks for any help! via /r/cars http://ift.tt/2sOihYn