content: Do NOT BCc to an offsite account - corporate mail programs have filters that check for this and it will be used as lawful grounds for your termination. Instead, archive emails to a thumb-drive.  Never use this itself as evidence because it establishes intent to defraud the company.  When needed, review the content of the mails and have your lawyer subpoena the email records for those dates.  The stash on the thumb-drive is purely for your personal reference to make sure they didn't 'accidentally' skip something.