Recently I went to a chain tire shop/garage. My left rear tire had a bulge just above the hub cap. I looked online and it appears that this could be really bad if I didn't fix it.
So, the serviceman told me that I should replace the rear two tires so that the wear is even going forward.
He also checked my spare tire. He said that because my car is a 2003, the spare should be replaced. So he took my good right rear tire and put that in the spare tire compartment.
The spare was never used...why did I need to replace it? When do I need to replace my spare? If I didn't go to the my tires services, I would have never thought to replace the spare.