Does all mail get staamped during processing

In the United States, the answer is generally yes, but there are some exceptions and nuances to consider.

The United States Postal Service (USPS) is required by law to affix postage to all mail pieces that are processed through their facilities. This is known as "postage affixation" or "stamping."

Here are some scenarios where mail might not get stamped during processing:

1. Pre-paid mail: If the mail piece has a pre-paid postage label or a pre-paid envelope, the postage has already been paid, and the USPS won't need to affix additional postage.
2. Free matter mail: Certain types of mail, such as free matter for the blind, free matter for the disabled, and free matter for the military, are exempt from postage requirements.
3. Metered mail: If a mail piece is sent using a postage meter, the postage is already affixed, and the USPS won't need to stamp it again.
4. Special handling: In some cases, mail may be processed without postage being affixed if it's being handled under special circumstances, such as being sent to a specific facility or being processed through a special program.
5. Error or exception: In rare cases, a mail piece might not get stamped due to an error or exception during processing. This could be due to a technical issue, a mistake by a postal worker, or other unforeseen circumstances.

It's worth noting that even if a mail piece doesn't get stamped during processing, it's still considered "postage due" if the recipient is required to pay for the postage. In these cases, the USPS will typically send a notice to the sender or the recipient requesting payment for the postage.