alt Hacker NewsYour zip plus 4 changes. It isn't worth trying to know as it isn't supposed to be constlnt. If you send a lot of mail there is a discount for using it but you have to update everyone's address often (iirt at least 4x per year)
Your zip plus 4 changes. It isn't worth trying to know as it isn't supposed to be constlnt. If you send a lot of mail there is a discount for using it but you have to update everyone's address often (iirt at least 4x per year)
Source? The numbers correspond to the USPS distribution centers and carrier routes. If the numbers are changing that would imply an increase in zip code subdivisions, making each zip code a better address predictor for a given individual.