Depends on what has been changed/replaced on your car in the past?
If you are not sure, change everything for peace of mind if you can afford it, ie;
Oil and Oil Filter
Spark Plugs
Fuel Filter
Air Filter
Cabin Filter
Haldex Oil and Filter (if you have an S3)
Gearbox Fluid
Brake Fluid
Coolant
Cambelt inc new roller, tensioner and dampner
Water Pump
Aux Belt
This is what I would change but you dont have to change it all, it would not be cheap but will give you peace of mind.:icon_thumright: