I am using Mobil 1 0W20, and am changing it every 7,500. I use the car for delivery. Not quite taxi service rough on the engine, but not quite freeway commuter easy on it, either.

When I change the oil it looks like it is ready to be changed, but doesn't look like black paint. Were I to let the oil go 7,500 miles in my Geo, that's exactly how it would have looked.