Set Default Admin List Screen Per-Page Count

<?php
add_filter( 'get_user_option_edit_post_per_page',     'scseed_default_per_page' );
add_filter( 'get_user_option_edit_page_per_page',     'scseed_default_per_page' );
add_filter( 'get_user_option_users_per_page',         'scseed_default_per_page' );
add_filter( 'get_user_option_comments_per_page',      'scseed_default_per_page' );
add_filter( 'get_user_option_upload_per_page',        'scseed_default_per_page' );

function scseed_default_per_page( $result ) {
    // Only override when the user has not explicitly set a preference yet
    if ( false === $result ) {
        return 25;
    }
    return $result;
}