Timely Oil Changes

jhilley wrote:
...It doesn't show the additives left, but it shows what is controlled by additives and whether or not they were with in normal ranges. As far as wear, how would you predict in advance? This tells you before your engine is ruined.

That is kind of why I have a problem with it. It shows that what you did was ok, and it would tell you if it was not OK, but you really don't know how much you have left. It would seem that you could send in a sample every 500 miles and then graph the results. When you see the cumulative wear rate start to increase, then you know at what point you would need to change the oil. While you could do that to create a base line, there are outside factors that can affect the the wear rate. So if you are going to push the limit, you don't know where the edge is.