It is totally right that even if you don't change your own oil you have to watch those people open the bottle of oil for your car. I got my oil changed by a regular oil change place yesterday and i caught them using no brand name oil which i presumed is low grade oil for my car. They also told me that my car need a new air filter. I then checked it out and I am sure it can be used for another 5000 miles. SO, never trust non-professional people on your own car....