PS -- I win!
66,000 KM!
I just changed mine last week, and I think I can beat that! 129,000km and I haven't changed it since I bought it 2 years ago at 72,000km... who know's when the previous owner did, by the looks of it never!
Made my own (and 5 more out of a Walmart 1" HEPA filter) that I bought for $14. Took less than 20 minutes including cutting, from start to finish, also sprayed it with febreeze and put a bounce sheet on top of it, smells like spring in the spring time mountains every morning now compared to dirty moth balls.