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I guess something like a trad strong IPA (8%+) might last OK? But there the hops is as much a preservative as anything and will mellow as the beer matures, as opposed to to a modern fresh hop bomb style that will go off.
But +1 for the suck it and see approach; worst case is just that it'll be flat and dull and need to be poured away, but you might get something rather interesting.
Depends what it is. If it's something hoppy then no, if it's something more malt based like a fullers vintage or yeast based such as Lambic or strong like a barleywine or impy stout then yes.