Australians get a choice of 32 or 64 page type. I travel a lot, and Ozzies need VISAS for pretty well every place on earth unfortunately, so even the 64 pagers fill for me pretty fast. They cost about $150 a passport as I recall, plus lots of paperwork so filling them is bad news. Pages will not be added. Fill it up and they void it, return it, holepunch it thru, charge you afresh, and off you go again.
I am trained now to sweetly ask customs guys to stamp on a page with some other stamps already on there. 90% oblige. Amazing how they otherwise all LOVE a white virginal page to plonk their cancel on.
------------------
~
Glen ~