How can all $_POST variables be reset at the end of includes to prevent repetition of the last operation with previously entered values?

To reset all $_POST variables at the end of includes to prevent repetition of the last operation with previously entered values, you can simply unset the $_POST array at the end of each include file. This will clear out any values stored in the $_POST array, ensuring that users do not accidentally resubmit the same data when navigating between pages.

// Code to unset $_POST variables at the end of includes
unset($_POST);