I have a 2005 saab 9-3 and I just took it to the dealer couple days ago to get it oil change and flush the trans oil. After is done they left a stick on my car saying my car need next service after 7000 miles. Since the car is full synthic isn't it suppose to last 15000 miles? According to manual it said 2 years or 15000 miles too. So I would like to know how often should I do oil change and usually how often do you guys do it?