What are the potential issues with using if-else statements in PHP for file existence checks?

Using if-else statements for file existence checks in PHP can lead to potential issues if the file path is incorrect or if the file is not accessible due to permissions. To avoid these issues, it's recommended to use PHP's built-in file functions like `file_exists()` which is specifically designed for this purpose.

$file_path = 'path/to/file.txt';

if (file_exists($file_path)) {
    echo 'File exists.';
} else {
    echo 'File does not exist or is not accessible.';
}