Originally Posted by hikeril
Any concerns with the spare being 4 years old?
If you had a flat tire and needed the spare, you would presumably continue to drive with it, especially if it was unused ... it's more dirty than worn. It has been "getting a free ride" while its four 'brothers' have been working. Think of this as getting use out of something that was included in the purchase price of the vehicle, but is as yet unused.
Tires have a finite life, but it is presumably measured in decades. The issue of "date stamping" tires was controversial, but the tire industry grudgingly complied. For a 2010 vehicle with five (5) full size original tires it is not an issue.
Note that this 'trick' only works once ... next time you will be buying four new tires and you probably should buy five to replace the spare.