Pickled Sausages do eventually expire but they remain safe to eat for at least 3 months past the expiration of the pickled sausages.
Pickled Sausages do not require any refrigeration to keep them good and prevent them from spoiling because they are made with some preservatives.
Pickled Sausages sit out at room temperature in bars, stores etc and never go bad for at least 3 months if not longer.
But most times the pickled sausages are eaten well before 3 months so it's never an issue.
I prefer to keep my pickled sausages in the refrigerator once I open them though just to keep them good longer and to prevent the potential of bacteria from growing on them.
But as long as the jar of pickled sausages remains sealed when you're not eating them then bacteria should not be able to grow on them and they should keep just fine.