Change filter - keep the oil
since my wagon is no longer under the maintenance plan, I've been changing oil every 10k miles. Last time, I took a sample to a local shop and they tested the oil [mobil 1]. While it looked used, the oil was not degraded. I changed the filter and one day later, the oil looked almost like new.
I've been told by distributors of synthetic oil for industrial machine customers that the oil can last for a very long time - its the filter which clogs up.
BMW filter placement allows for filter changes without dumping oil. Has anyone else tried this.