I pulled my K&N's at 10,000 miles run time, concurrent with a scheduled oil change. They looked a lot like Andrew's. You can actually see the air flow pattern over the filter from the dust that is caught. It is easy to pull, clean and "recharge" the element with the kit. Just do it and protect your ride. For me its more than a matter of how long can I go before I have to change a filter. Its a matter of how can I best protect my machine.