On new cars/trucks/SUV.
Change oil religiously every 3,000 miles no matter what the manual states.
If you plan on keeping vehicle for awhile it is crucial to do the frequent oil changes in the beginning. Once the car starts to burn oil later on it is too late.
Don't go for the cheapy oil change either. Oil filter come in about 3 grades.
Motor oil starts to deteriorate immediately. Synthetic oil deteriorates more slowly.
There is a web site dedicated to motor/engine oil:
LINK