This depends on which Filter Kit you chose; Primary or Secondary.
Primary filters need changing more often than Secondary because they are filtering fuel straight from the tank, whereas Secondary filters don’t need to be changed very often because they are filtering fuel that’s been through the factory filter. So this is the general rule:
• For Primary filters we recommend you replace the cartridge every 20,000kms.
• For Secondary filters we recommend you replace the cartridge every 40,000kms, or every second time you change your factory filter, whichever comes first.
The exception to the above rule would be if you encountered contaminated fuel, in which case you should change the filters early.