I try and change the oil in every car I have owned at 3000 miles. I changed the oil in my R/T at 2400 the first time . Because I had it in the dealer for a engine check light code. Crank sensor . That they reset . And so far no more problems. I use the Castro GTX 5W20 regular oil in my car. The dealer let's me bring it . And they change the filter and only charge for the labor. They admitted they sometime don't have the 5 W 20 recemended and use bulk 5 or 10 W 30 or 40 . As do many other dealers or change brands from time to time per suppliers. Not something I want to do . This way I know what goes in every time . I've never used the synithic oil . I'd rathter change more often . Than later.