I have a 2013 JKU and need new tires. The spare has never been used. Date code for tires is 3812, or mid-September 2012. Car is always garaged, so spare tire has had minimal exposure to sun. My understanding is that the spare has TPMS.
Should I:
1. get four new tires or
2. just get three, use the spare as a primary, and use the best remaining tire as the spare?