Does knowledge have an expiry date?
Is there an expiry date to knowledge? I dont think so, because what is knowledge today will always be relevent and helpful. Unless proved otherwise. Even when old knowledge is replaced with new information, the old is useful. By studying the old, one comes to know how you got to where you are today.
But it also depends on how important the knowledge is. It makes no sense in keeping all the acounts statements or all the purchase orders that a company made since it was started ( it may have to maintain these records for a certain time frame as per government rules - excise department). IT depends then on what kind of knowledge are we talking about.