As a result of the changes, the Postal Service says some regions and local areas will receive 2-3-day turnaround service ...

The following is a list of how service standards will be changed, according to the Postal Service fact sheet: Moving from a 3-digit to 3-digit zip code pairing ... A USPS map is available online ...

Though the changes are intended to cut costs and improve efficiency, millions of Americans could also see a decline in certain services.

These could include "2-3-day turnaround ... Five-digit zip code add-ons are meant to streamline sorting and delivery as compared the current three-digit pairs. The USPS now has a map online ...

The new service standards provide more precise expectations for mailers, as they are based on 5-Digit ZIP code pairs, rather than current standards that are based on 3-Digit ZIP code pairs.