All champagnes can go bad, but a high quality vintage champagne like Dom Perignon has a shelf life of 20 years or more. This assumes that the bottle has been properly stored, preferably in a refrigerator. Improper storage can greatly reduce the shelf life of any wine.
While experts have long advised people to store champagne in a cellar, refrigeration prolongs shelf life better, according to a 2014 study by the American Chemical Society's Journal of Agriculture and Food Chemistry. Champagne that has gone bad tends to be less bubbly, and may have a musty smell and a flat or sour taste.