The United States Postal Service (USPS) has announced its recommended mailing and shipping dates for holiday mail and packages to ensure timely delivery before Christmas Day on December 25.  USPS Ground Advantage service and First-Class Mail service mailings must be sent by December 18, while Priority Mail service should be completed by December 19, and Priority Mail Express service by December 21.  For Alaska and Hawaii, USPS Ground Advantage service mailings need to be in by December 16, with other services following shortly after. International mail pieces should be sent earlier in December, with specific recommendations for different regions. USPS advises customers to plan ahead and ship early this holiday season to avoid delays. Source: People