You can have alcohol in your checked baggage or with you as hand baggage to most destinations as long as you do not exceed the inbound customs allowance limit. But, for Australia liquids such as duty free liquors need to be sent as checked baggage and not carried by hand.
you can check all the duty free questions at dutyfreeonarrival.com
If you are aged 18 years or over, you can bring 2.25 litres of alcohol duty-free into Australia with you.
There is no federal limit on duty free liquor that is brought into the United States. There are states that have personal use limits that can limit the duty free liquor brought into the US. A person has to be entering a state with a limit to be affected by this rule. Each state has a different limit.
you can check all wordwide duty free allowances and limits at this website where it has all duty free shopping information dutyfreeonarrival.com
The duty is $8 per 1 case (24 cans of beer). I would imagine the same would be true for 1 liter of hard alcohol. Beer in Canada costs about $26 - $36 per case and around $36 for a liter of hard alcohol.
There is a relatively small duty free allowance. After that, duty must be paid.
800 dollars per person (in general).
Yes, you can buy duty free when travelling between Ireland and Switzerland. There are limits with regards to the amount of alcohol and tobacco that can be considered duty free.