While some changes will largely be behind-the-scenes, other changes – such as mail delivery times – will be more noticeable.

The USPS is implementing new service standards for first-class mail, periodicals, marketing mail, and package services.

The changes hitting USPS this month, which took effect April 1, are part of a 10-year plan to save the agency $36 billion.

The changes, which are being rolled out in two phases, is expected to save the Postal Service billions of dollars over 10 ...