First time was around 30K miles, but the bike was running just fine when I changed it. Kept the old one. Next time about 50K and that's the one that's in it now, plus I've got the two for spares. I've not had any issues with the filter so far and will likely just use this one until it gives problems, then put one of the others on before buying a new one. But then again I'm a cheap bastard.