The reason I ask is that I appreciate the oil is normally changed at 12000mile servicing. Isn't that a little long between oil changes? I have always changed my car's engine oil (a) myself (to guarantee it is done properly with the correct oil and spares) and (b) to to ensure it is fresh. Old oil degrades and that's when the engine wear starts to accelerate.
So - I don't plan to wait for 2 years/12000 miles to have my oil changed, hence the question.