The answer is that it depends....this pic is the sidewall of the Bridgstone Dueller Revo 2's I had on the Suburban. Still plenty of tread left but this is what the sidewalls looked like at 5 years old. I wound up replacing these prior to the camping season that year (2019 IIRC).
I wouldn't automatically run out and replace tires that are 6 years old, but start watching them closely, look both on the sidewall and in between the tread block for signs of cracking. If you park in the garage so tires don't get UV damage so might get 10+ years from them.