In spring of 2017, we purchased a used 2010 Landmark Augusta. The fiver has four Goodyear G614s all manufactured in late 2014. The spare however, is a GY 614 that was manufactured in late 2009. My suspicion is that the previous owned replaced all 4 tires in 2014-15 and kept the original spare. All five of the tires are in good shape, so I'm in no hurry to replace the four tires in use but am unsure about whether I need to preemptively replace the 9 year old spare. Thoughts?