Do I Need to NCOA My Data File? In a Word, Yes.

National Change of Address (NCOA) is the USPS registry of people who move or change their address. The Post Office requires all First-Class Mail and Standard Mail lists to be run through the NCOA database and updated within 95 days prior to mailing, in order to qualify for automated postage rates.

National Change of Address - NCOA Services

Updating NCOA Changes for Maximum Postage Discounts

A key component to the effectiveness of NCOA processing is updating the changes in your house file. The NCOA system maintains updates for 48 months and after that time, the address changes are removed from the USPS database. 

What this means to you: if the addresses in your mail file are not changed in your internal database, after 48 months the addresses will no longer be corrected through NCOA for you. Customers or prospects who have moved and not been updated in your file will potentially no longer receive your mail. And, if a high enough percentage of your list falls out of compliance with the Move Update standard, you may no longer qualify for discounted postage.