“The CAN-SPAM Act requires that an unsubscribe link be present in every campaign that you send. The unsubscribe link must work for at least 30 days after sending.”
Ensure your ‘unsubscribe’ button always works. Any subscriber who wants to stop receiving your emails but finds the unsubscribe button isn’t functioning will become annoyed and possibly send your emails to the spam folder. Check that the button works before launching new email campaigns.