I do mine every 6K miles, which tends to be every 4-5 months. For our cars which do less mileage i do them every 6 months.
I always use geniune or good quality filters and the correct make and grade of oil in each car.
I dont understand long life servicing, oil doesnt last that long. It gets mixed with the fuel and carbon, losing its lubricating and cooling factors.
It costs virtually nothing to do an oil and filter change, but might save you money in the long run.
Im very keen on servicing, you can never service too often!
