every 5k using castrol edge synthetic oil and mobil 1 filter. the runner has 74k
on it know and havent had one problem. im sure your going to get a whole lot of different opinions on this.
With synthetic I consider time being a factor vs miles to a point. My 4Runner only sees about 9k miles a year and I change mine between 8-9k or by the 11th month using M1 and a Puralator PureOne filter. I just make sure I don't go longer than a year between changes.