Yeah, that's one of those "how big is your yardstick" things. I remember going through a thread on the IMOC forum over this very conversation. The oils that we buy are premium, well they should be, and they are designed to look after our engines very well. The engine wear, once broken in, of decent performance cars is at a minimum and most of the carbons are burned off in the engine as long as it is used a couple of times a week. Mileage dependant once per year is more than adequate. If you are doing 12k per year then I would definitely recommend twice per year as about 8k is the maximum I would take a car like this. When you are doing a limited mileage of 0-8k once per year is absolutely plenty.
There are obviously exceptions to this. I would ALWAYS recommend an oil change soon after any trackday or major 1/4 mile day. At these events if the engine is pushed the oil will be seeing high temps, as well as the coolant etc, and wear will be a little premature. For safetys sake I would always do a full service after such an event.
In JPs case I would probably recommend servicing every 3 months