[fetchmail]should UIDL be used or not?

Hi,

I've been trying to understand the importance of the
uidl option.

In this sample .fetchmailrc config file
---------
poll server.com protocol POP3 options uidl username "xyz" password "abc"
---------

If I remove the 'options uidl' setting, will I loose any email if my dial up
connection breaks during a download?

What purpose does the uidl option provide? I read the man page and did not
understand too much. Can anyone help explain?

Thanks

Regards

Rishi