I am curious to know how long a bottle of bourbon lasts opened and unopened as well as if others considered corked bourbon preservation.

1) How long will bourbon taste great unopened?
2) How long will bourbon taste great after opening it?
3) Do stores throw out old bourbon or does it sit there until one of us grabs it?
4) Does bourbon get better, worse, or go unchanged in the bottle sitting in your bunker unopened for two years?
5) What is the best way to keep corked bourbon? Is it necessary to keep the cork wet i.e. lying it on it's side like wine?

Thanks