Different types of chocolates can be stored for different periods. e.g dark chocolate can theoretically be stored for a period of 10 years but that is doing is a bit over, but in places where it can be affected with moisture, the chocolate will develop white crystals on the top due to sugar and the ideal storage period is not more than 9 months. Milk chocolate on the other hand should not be used after 6 months, umm let me rephrase that .. its better not to use it after 6 months. It isn't necessary that it will go bad.

Storing in either humid or too hot an environment reduces the shelf life. And why are you storing chocolate for such a long time. Send some over if its too much :p