Old wives tail about tires, true or not?

[wbedwards]

Up till now, I would not replace tires that had good tread and weren't cracked or dry-rotted. That has all changed in the last two years. I bought a car with 5 year old radials that weren't cracked and had great tread. One had an internal separation I caught while rotating the tires and I replaced it. The second one separated internally on a long trip and you could feel it driving real slow. If I had kept on driving, it would have come apart. I replaced that whole set and replaced another set on another vehicle that were 8.5 years old and looked perfect. I don't want a blow out at any speed.