I vote every 30k. If you going to leave it in. Other then that, this is what I would do. 1) Check it at 30k, if filter bolts are clean. Remove them, because you oil & filter for your OCI's is doing it'd job. If dirty; 2) Replace filter bolts with new\clean ones. Upgrade to a better oil & filter. Recheck 30k later. repeat 1&2 until the filter bolts are clean, so you can get rid of them.
What I did & why I did it.