I know of at least one person who was invited to get a Centurion card ..... twice .... (without filing an expression of interest) whose monthly spend was around A$10-12k. Mine is roughly the same although it does spike to A$20-40k
He accepted the first offer and held the card for a few years before reverting to the Platinum. He received the second invite about 5yrs later and accepted again and still has it.
With roughly the same spend, I have never received an invite. I have not & will not file an EOI. The only difference is that he has held an Amex since the mid 80s. I had my first in the early 90s but I've had breaks in membership.
