> they often retain their potency for many years after the supposed expiration date With the exception of few drugs that do go bad "often" is not good enough,

> they often retain their potency for many years after the supposed expiration date With the exception of few drugs that do go bad "often" is not good enough, AFAIU it's a statistical game of certainties- I want to be X% certain that the drug has Y% of its potency