You can include the same php script more than once by using include directive, output from the example below confirm this:
a.php
<?php
echo "Test \n";
b.php
<?php
include("a.php");
include("a.php");
calling b.php prints the following:
Test
Test
Yes, we can use include("xyz.php") two times but, this is not a good practice. If you have defined any class or function in that file then it will be redefined and PHP throws an error.
yea you can include the file as many as you want since you are using include() or require();
if you want to include the file ONLY once ,, you can use include_once(); or require_once();