Davey

I do 6 month intervals or 5K miles whichever comes first, which is always 6 months. I enjoy making obese, greasy kittens.

As far as the "oil light" thing, it's oil pressure, as was already pointed out. You won't lose oil pressure from low oil until it is way too low. However your engine can be full of oil and you can lose oil pressure, so it's important to know what you are looking at. If you thought "Hey the oil light is on" so you checked the dipstick and it read full, would you think it was a malfunction of your "oil light"? That could be a costly mistake. Again, know what you are looking at.