Rob, I recommend once a year as you do, and I change it every spring after I drive it a few times before the spring Dragon Run. The discussion at the garage is when in that year should you change it?

Some say to change it before you put it away for the winter. That way you have the old oil out, which probably has some contaminates and acid in it, just sitting in the oil pan and engine.

Either way has pros and cons.

But once a year for sure for me! James