we have also the same doubt.
Running netstat -lpn gives
tcp 0 0 0.0.0.0:143 0.0.0.0:* LISTEN 5578/xinetd
disabling xinetd will affect imap service? By the way this is a cpimap server. Is there a way to avoid this or xinetd must run if you have cpimap?
I have other server running maildir with courierimap and xinetd is not used so I could disabled it.
Thanks