Another plus for DIY oil changes is if you keep a sample of the oil you can send it to a test lab for analysis. This is what all the major fleets do. Engine wear shows up in the oil ... metal contamination. My last test cost me $20. Now I know my engine is fine and if I sell her, I will demand top $ because I can prove the engine and my manit. quality.
Also I have seen a kid taking Mobil 1 home after filling up a customers car with P-Oil!
Never trust a kid with a luxury car.