In the HSC courses (2U, 3U, 4U), only use degrees for trigonometric calculations i.e. sides of triangles etc.
Any other content, use radians, unless of course it says degrees. Be careful with sketches, they will give you either degrees or radians to use.
A good idea would be to take two calculators into the exam, but put a red rubber band around one which is always on radians. Good Luck!
Note: Applications of Calculus to the Physical World, Newtons Method etc. use RADIANS.