once in the liftime around 80-120K miles seems to be average. but depends on environment near the sea half that etc I see you are in Car Na Daaa, which is pretty harsh, dont know if they use salt on the roads etc but it kills under car componants, stupid place to put the fuel filter if you ask me, right next to the rear wheel, some have relocated it but its a faff to do so. You can fabricate a better guard for it but it still gets hammered, its basically getting jet washed with salty water grit everytime you drive it