I agree with the Arm, but you should use common sense.
Eg, If I was joining straight in and made a five mile final call, I would like to hear, for example, a downwind call if you were the only other aircraft at the aerodrome (as CASA calls it
)
Otherwise, if you are the only one doing circuits, a base call every circuit would be adequate for the arrivals who dial up the freq at 10-15 nm.
ID