I disagree wholeheartedly mr flappy - until the RAAF commenced providing 7-day ATC services at Newcastle, it wasn't uncommon for inbound 737/A320 to make calls at 50-60 miles, again at 25, and then every 5 miles from 15, and still end up in a massive balls-up as someone in a Jabiru or something crossed the Newcastle City CTAF boundary to the south (limit: Hunter River, about 5NM away from the AD) and entered the Newcastle CTAF, in between calls from the jet, and for both concerned to end up with a surprise windscreen full of the other.
Likewise, there are strips like Bathurst or Cessnock where an over-anxious CPL student just can't help themselves from broadcasting engine start, taxiing on alpha, entering 30, backtracking 30, lining up 30, rolling 30, airborne 30, crosswind 30, downwind 30, scratching left nut, had weeties for breakfast etc while the one or two other low-performance aircraft in the area pass through all the phases of rage and frustration to end up gibbering messes in their cockpits while they try to squeeze in an estimate or a request for the cloud base.
It makes far more sense for CTAFs - which are, let's note, a procedure whose risk tolerance is designed around low-density/low-frequency aerodromes - to be of varying size and dimension according to aircraft performance and traffic conditions, and leave it to the professionalism and airmanship of the pilots within it to determine at what point, and with what frequency, they broadcast. If pilots aren't professional/competent enough to manage that, it's beyond the scope of AIP to regulate common sense.
In any case, most of the people who struggle to determine what's appropriate for a particular CTAF probably haven't picked up a copy of AIP since their GFPT - I still run into pilots who remain completely ignorant that we ever went to CTAF(R), let alone got rid of them again!