In what situations should PHP developers consider using custom functions for text manipulation in forum posts, and how can they ensure the functions are efficient and error-free?

PHP developers should consider using custom functions for text manipulation in forum posts when they need to consistently apply the same formatting or modifications to multiple posts. To ensure the functions are efficient and error-free, developers should thoroughly test them with various input scenarios and handle edge cases gracefully.

// Example custom function for text manipulation in forum posts
function formatForumPost($postContent) {
    // Add custom formatting logic here
    $formattedPost = strtoupper($postContent); // Example: convert post content to uppercase
    return $formattedPost;
}

// Example usage of the custom function
$postContent = "This is a forum post.";
$formattedPost = formatForumPost($postContent);
echo $formattedPost; // Output: THIS IS A FORUM POST.