I don't change the oil all that often (maybe every 8000 miles) and on my 10 year old car the oil light comes on and I need to add a quart or two (and then I start thinking I practically changed the oil and don't need to worry for another few thousand miles!). Does that mean it's leaking for sure? Or does oil make it's way though the pistons in an older car and burn off in the combustion process?
Note there are no (new) spots on my driveway.