oem airfilter will last longer than 12k. I tested a brand new filter against one with 10k on it and there was no difference on the airflow meter using a spare airbox I have. The 10k one looked dirty but it means nothing. there were similar test done on
www.bobistheoilguy.com with car filters. They also last must longer than the recomended changeout. I guess the filter manufactures want to sell more filters like the 3k mile oil change interval recomended by the oil companies.