Both plaintiffs and defendants are often frustrated because official USPS records of the disposition of Certified Mail are only retained for two years. Often, litigation in a matter does not even begin until more than two years after the situation being litigated have passed.
Recently I have had several firms ask me if they could use USPS Form 152 instead of the more costly Certified Mail most commonly used to provide proof of receipt. The short answer is no.
The United States Postal Service offers two services which document that a letter has been placed in the mail at a certain place on a certain date; Certified Mail and a Certificate of Mailing.