Try not to go below 5 minutes. Enable the save password only if the computer is your personal machine. The Send on check is an optional feature that some like and others do not. It makes Eudora wait until the next time it checks for email before the email is sent. At this point you must make a choice.
POP is the best choice for most users.
This method pulls the email from the server to your computer. If you use only one computer, then POP without any options checked is your best choice. If you need access to email from more than one computer, then decide which computer is the primary and which is the secondary computer. The primary computer should leave mail on server for a few days. The secondary computer should be set for leave mail on server indefinitely.