Yes Almond milk does eventually go bad even when you haven't opened the Almond Milk.
When the Almond Milk has been opened it should be used within 7 days of refrigeration and opening of the milk.
Even when you have not opened the Almond Milk it will only last for a week past the use by date so make sure you drink the Almond Milk within a week past the used by date.
The sooner you drink the Almond Milk though the better it will taste.
But Almond Milk will not keep forever though even when refrigerated so make sure you use it up and refrigerate the Almond Milk at all times even when you haven't opened it.
Almond Milk usually lasts a bit longer than regular cow milk but Almond Milk will eventually spoil though.