Careful BIRD FREAK and KAYTEG1, you are proving my point.
IMHO many people have been taken in by tire marketers (not manufacturers) warning about scrapping perfectly good tires at a very early age; 5 or 6 years.
As I have stated repeatedly, in my 40 years in the tire industry a very low percentage of failures I saw was attributed to age, yet it is automatically blamed by so many people who don't have a clue, except what the marketers have pounded into their heads.
My continued advice: Go to the tire MANUFACTURER'S website and follow their recommendations on tire care, including age of replacement. Don't follow some marketers veiled threat about how they will automatically blow out at 5 or 6 years.