Because my car is modified I change it every year, basically I have an annual service regardless of mileage - at the end of the day I suppose the oil is your blood and needs to be looked after. Also, I have heard that sludge or something similar can form on the 1.8T's which can be troublesome so having it flushed more often than not should always help.
Twice a year for mine[/QUO
Mine was done approx. 6000 miles ago when I had the oil pick up pipe replaced so I think I will book it in for an oil change.
every 10000 miles or about every 6 months, its a 1.9 TDI. use castrol edge 5w/30. which at the moment is on special offer at opie oils.
The audi oil is exactly the same as the castrol edge on sale at halfords, no different, they've just seperated the branding & audi retain SLX & retail is now Edge.