I have typically changed oil AND filter around every 25-30 hours on my IO-520BB. My mechanic at annual recommended I change oil every 25 hours, and filter every 50 -thus change filter every other oil change. He is a big proponent of keeping fresh / clean oil in the engine. Historically we have cut open filter to inspect and send off oil for analysis and everything looks healthy. I like the idea of doing this 25/50 but curious on using the filter all the way to "TBO". Happy Thanksgiving everyone!