Tires: Tire age on Blazer, size blazer, high mileage

Question
I have a 1989 Full size Blazer. It has always been garaged. It has less then 90.000 miles on it.
After the tires that came with the Blazer wore out we replaced them with Michelin high mileage tires from Sam's club about 14 years ago and want to know if the tires are still safe to use do to age?
The tires have just been rotated and balanced at Sam's Club. Nothing was said about AGE. And there is a lot of thread depth left on them.
We do not use the Blazer for long trips anymore just around town and in the winter when it snows. As we have another car for that.

Thank you

J. Davidson

Answer
John,

Recent bulletins from the tire industry indicate that tires degrade simply due to time.  The age of a tire is important even if the tire is unused.  There some disagreement over how to best express this age limitation, but my take is:

If you live in a hot climate (AZ, CA, NV, TX, and FL) then the limit is six years.  If you live in a cold climate (MN, ND, WI, MT, etc), then the limit is 10 years.  States in between are  ..... ah ........ in between.

No matter which state you live in, 14 years is way beyond the limits being published.