Once you reserve a PO Box at the Post Office location, link it to your USPS.com account. You can manage it online instead of the Post Office location. Link a PO Box to an USPS.com Account
Quick Answer. Cashier's checks themselves do not expire as personal checks do. However, the funds behind the check are subject to state escheat laws.
yes there is... As there is on most all major business or government checks...but that is for safety and concerns the check itself not an expiration on what they are paying. If you have an expired check that was never cashed it is a simple process to have the check replaced with a new one.