A lot of folks talk about tire age and when they "age out."
Here is what a few tire companies have to say:
Passenger & Light Truck Service Life
Japan Automotive Tyre Manufacturers Association (JATMA) recommendation: At 5 years have tires inspected by "Qualified tire service person" and no matter the condition replace any tire at 10 years.
Bridgestone & Firestone issued a Tech Bulletin that supports the 10-year maximum but advises that "some tires will need to be replaced before 10 years due to operational conditions.
Michelin, Falkin, Yokohama and Vredestein suggest tires be inspected by specialist annually starting at 5 years and replaced at 10 years as a precaution "even if such tires appear serviceable and even if they have not reached the legal wear limit"
GM recommends tires be replaced after 6 years
Hankook says to replace tires 10 years after manufacture "even if the tire was never used"
Goodyear, Continental and Cooper do not give a maximum calendar age but stresses "Monthly Inspection" along with proper storage and monitoring of inflation pressure.
Kumho says to have tires inspected annually starting at 6 years and to replace the tires at 10 years, even if the tires appear serviceable.
Vredestein suggests tires be inspected by specialist annually starting at 5 years and replaced at 10 years as a precaution even if such tires appear serviceable and even if they have not reached the legal wear limit. They also say that tires on trailers, campers, horse trailers and caravans (motorhomes) be replaced at 8 years.
They are talking about the annual inspections after 5 years to be done by a "Tire Specialist", not just anyone that sells tires. I would suggest that when having this inspection done you ask for a written assessment as a minimum. You can ask if the dealer has an ATS Certified Technician on staff.