An Australian Young Fogey
See this post by him: Why I am a Monarchist
Monarchy is cheap and efficient. We have had over a century of politicial stability thanks to the Crowns check on political power, and we pay very little for it. The annual cost of the Governor General, the Governors and their respective staff and residence is nothing compared with the cost of to the taxpayer of our politicians and their staff and allowances and whatnot (I do not begrudge them any of that, so long as it is not abused). The cost of the Monarch herself (or himself, as it will be again in the future) is technically born by Her British subjects, but even then the annual allowance of fifty million pounds or whatever it may be exactly is more than offset by the hundreds of millions of pounds the Crown Estate (the income of which is granted to the Government by the Monarch in exchange for said allowance) generates per annum.
It may be that we could develop an institution that will provide the checks and balances of our present system under a republic, but how much more expensive will that be to initiate and maintain? How many independent watch dogs and committes will it require? We have a remarkably effective system at very little cost.