Is it necessary to use "exit();" after a header redirect in PHP, and what are the implications if it is not used?

It is not necessary to use "exit();" after a header redirect in PHP, but it is recommended to prevent any further code execution that may be present after the redirect. If "exit();" is not used, the script will continue to execute, potentially causing unexpected behavior or errors.

header("Location: newpage.php");
exit();