I have 330,000 miles on my 2006 Mercedes E320, I have been changing the oil now at 15,000 miles and considering going to 20,000 miles per change (as owners manual says 13,000 miles), not the 10,000 recommended by the dealers. I have had oil analysis done at 15,000 miles and the analysis says that I should try 17,000 - if good then go to 20,000. It uses < 0.5 quart per 15,000 mile change - only slight increase in viscosity. I also use in my 2009 Audi Q5, (120,000 miles on it) and considering going 20,000 miles like the owners manual says.... (I drive a lot). I tow a trailer with the Q5 and has used about a quart in 15,000 miles. Oil analysis shows very low corrosion products, with great inhibitor levels remaining.