I wanted 5 litres of the 'product' from the shady young dude with half a tache behind the counter, And after 5 minutes I was handed 'the Merchandise' in a very poosh Audi bag and relieved of a very large amount of wonga. 5 single litre bottles Audi are you taking the pishhh

No w I know Audi state 20,000 between services but I certainly do not intend to leave a car that long no matter how good Audi's patter is. How the car uses a bit of oil when driven hard so I will be topping up but do I really need Castrol Edge Proffessional longlife III 5W - 30 ' liquid crack' ?
So given I will be changing the oil every 5,000 miles or so ( cars average yearly mileage so every 12 months at least ) I would like to know if there is a similar/better alternative to this stuff.