What issues are there with the 2006 Cadillac dts

Do you do a lot of around town driving or highway? Ever which one it is, I change oil at 5,000 for around town and 7,500 for truly on the road driving. I mean all real highway. A car your age should not require synthetic oil but they say you can go longer on a change, as much as 10,000 miles depending on the vehicle. I would not go that long but that's me. You went 1,000 on a real oil change. Probably will not hurt too much the first time, but if you make it a habit will cause issues down the road.