Temporary or permanent redirect

When do you do a temporary redirect versus a permanent redirect?

 

temp redirection only if it is temporary - hence during maintenance mode for example valid minutes or hours

permanent - such as
redirect 301 /old-dir/old-page.html http: // www . your-new-url . com / new-page.html

if site structure, folder-name, domain name or file name has permanently changed

 

Thanks for the info!