Most new European bought cars in the last 5 years or so only require you to do oil changes every 20,000 to 30,000 kms (about every 12,000 to 18,000 miles), which is a lot better than the 5000 kms (3000 miles) it used to be. Some car dealerships still try to sell you on the "every 5000 kms rule" because they claim "it's better" (for who?). I wonder who still falls for that one, since even the manufacturers claim you're still covered by the warranty as long as you stick to the 'every 20.000 km rule - or 30.000, depending on the brand.

For me 20,000 kms is about the distance I drive per year, so I simply use the credo: every 25,000 kms or once per year.