It is time to once again replace my Elkridge 292 Extreme Lite trailer tires. I am planning on gettting Goodyear Endurance ST 225/75 R 15 E1 tires. The spare which has been on the ground for all of 15 miles is 6 years old and will probably replace that also. Now for the question. Should I include the spare in the rotation cycle. The spare is a steel vs alloy wheel. I can live with the difference in looks if it means I actually get to wear out the spare rather than discarding a tire that has never been on the ground due to age of tire.