Best before dates do not mean things cease to be edible. It just means that it's at it's best quality before that date. There is a law that states that all edible food has to have a best before date, whether or not the food will spoil or not.
All that will happen to a cracker is that it may taste stale months after the best before date. If you don't mind eating stale tasting crackers, you won't get sick from them
Now perishable items such as eggs, milk, meat... now those are things you want to pay attention to where "expiry" dates are concerned.
Things like crackers, spices, dry goods, bottled sauces such as ketchup, soy sauce etc, can be used many months after the "best before" date.
Baking power and yeast can also be used years after the best before date. However, the effectiveness to produce a quality rise may be decreased. Which is why it's always best to "proof" your yeast before adding it to your baking.