Well I change the oil and filter in my Saab 9-3 1.9, every 5000 miles without fail. It takes me around 7 months to cover 5k. I carry out the oil and filter change myself, very easy job now that I have spent £25 installing a Fumoto quickvalve:
http://quickvalve.co.uk/
5 litres of 5w30 ACEA C3 low saps oil for my car, of which I use 4.3 litres (not for 500's), costs me no more than £20, buy it off ebay and that includes postage. A genuine Mann Hummel oil filter costs £4.50. Fuel filter, £15, but that only gets changed every 15 to 18 months.
Upshot of my 'overkill' oil changes, are a very clean engine, virtually no soot build up in the EGR, no DPF problems and the car passes its emissions test with a virtually nil reading on the analyser, every year.
Servicing your own car can be done very economically and I could easily carry out a intermediate service on a 1.2 500 having bought all the service items and parts myself, for less than £100, to include all of the parts that John202020 listed, minus wiper blades.
The only reason I would ever take a car outside of warranty to a main dealership, would be to have safety recall work done, diagnostics (updating software/ECU) or, if I didn't have a full dealership service history, I might 'treat' the car to a one off visit to ensure that everything was in order.