Totally agree with DragRace above. These days the raw material quality is so improved that drain periods can be extended. A BMW Longlife Oil can last for 18,750 miles. DaimlerChrysler has specifications like MB 229.1; 229.3; 229.5; 229.51; 228.1; 228.3; 228.5 and 228.51 and oils meeting these specns can last for 18,750 - 25,000 miles. Fiat approved ACEA specification can go upto 15,625 miles. Ford approved oil can be used in Ford cars upto 12,500 miles. Opel has an approved longlife oil which can go upto 18,750 miles. Porsche approved engine oil can last for 12,500 miles in Ford cars. PSA (Peugeot-Citroen) has the PSA approved oil that can last till 9,375 - 18,750 miles. Renault recommends the use of ACEA A3/B3, B4 level engine oil similarly. VAG (VW, Audi, Seat) approve the VW approved oils (standard service) till 9,375 miles and Longlife service till 18,750 - 31,250 miles.