At least a year or more.
Alcohol doesn't spoil
2 months.
No, but it adds a lot of complexity to the nose (smell) of the whiskey. Whiskey drinkers call this effect, "opening the bouquet."
You might be thinking of a whiskey decanter. It is a glass holder similar to a wine decanter, but it has a stopper. I don't think that they are for long term storage, but for opening the flavor at the time of drinking, for presentation, and show.
1minute
Following the opening of Colosseum Flavium (in 80AD) there were 100 holidays.
The Last Drink of Whiskey - 1914 was released on: USA: 7 June 1914
it will finish around 12.30am , ie last approx 3.5 hrs.
About two weeks excluding the opening and closing ceremonies.
I wouldn't leave it longer than 3-4 days after opening.
When was Last time Bengals won a opening game?
It will last 1 year after opening. Otherwise, indefinitely (note, this is not the same as infinitely long. We've just never kept a sealed tub long enough to know when the contents spoil).