What best practices should be followed when dealing with file and directory permissions in PHP scripts?

When dealing with file and directory permissions in PHP scripts, it is important to follow best practices to ensure security and prevent unauthorized access. One common approach is to set appropriate permissions on files and directories, such as restricting write access to sensitive files. Additionally, it is recommended to use PHP's built-in functions like `chmod()` to set permissions programmatically.

// Set appropriate permissions on a file
chmod("example.txt", 0644);

// Set appropriate permissions on a directory
chmod("uploads", 0755);