Just had my 30,000km service at 25.000km (18mths) Tyres rotated for the 2nd time incl. the spare. Seem to be going very good on Mackay Roads. incl. dirt, highway and pot holed roads. Bob Jane also confirmed good to get wheel alignments at every 10K so mine going in within the next fortnight to get its 1st (oops) and also confirmed 4 wheels all need to be aligned on the Calais or the 19's not just the front.
Still well over half the life left. I'm hoping for 50,000. Bob Jane person said average is prob 40,000 to 45,000 depending on how you look after them. I've had tyre pressure between 32-36 psi but was told by them and confirmed above by different poster that although 40psi maybe be a rougher ride tyres will last longer and will be make a big difference over the entirety of the life. So 40psi from now on
I'm no expert just passing on the comments from the tyre place.