I think it is a matter of personal preference of when to change it. We had a poll awhile back asking members which they prefer so you might search for it. I am old-school about changing mine and have the dealer change mine (I got the free oil change package when I bought my truck new) so the little sticker they put on my windshield tells me the mileage to bring it back in (usually 3K miles). On my wifes 2001 Suburban, the light comes on to remind you but on my 2006 Silverado it tells me what my engine oil life is (like 78%) as well as my fuel filter life (maybe only diesel here).