Grog is a waste of time unless it’s something rare or exotic.
It baffles me why people lug around large bottles of generic stuff like Jim Beam across the world to save maybe $10 against the Dan Murphys price.
		
		
	 
Actually it's a hell of a lot cheaper to buy retail overseas and pack it in your checked luggage.   The same bottle that costs A$60 at Dan's will usually cost around US$10-15 at a US supermarket.   It will be more at a US airport duty free.
But yes, given the bother, I only do this for stuff I can't buy here (which is actually a lot).
	
		
	
	
		
		
			Reading through the 
duty free concessions on alcohol, am I correct in understanding that it doesn't matter whether or not you paid taxes/duties on your alcohol purchased overseas, if you exceed the limit you will need to declare and pay Australian duties, meaning potentially paying tax on it twice?
		
 
		
	 
Almost every trip I go on, I exceed the duty free limit for alcohol, usually in the range of 5-10L (only the upper end if I'm travelling with someone, as there's a dangerous goods limit of 5L for spirits above 23% ABV).
I 
always declare - that's the most important thing.  I'm completely upfront when questioned, stating how much I have.  Around 80% of the time, I'm given a "just this time we'll waive it through.    I've had to pay duty about 3 times, only once was the full amount, others they did stuff like charge it all at the lowest ABV or leave off a couple of bottles.    To save time I actually do up a sheet with a list of what I have, the volume, ABV and LAL (litres of pure alcohol), purchase price and country of origin.    This usually makes the process a lot quicker if they do decide to charge (once an officer questioned how I knew the term LAL and I think had a suspicion I was a professional importer, I just said I like booze)
Usually I come through SYD or BNE, I don't think I've ever been charged at SYD - once they attempted to but the person responsible was on a break.  BNE much more likely to get charged.