I can really only speak to EEPC - not using EEFF.
As far as I'm aware EEPC doesn't have a place to enter a license file or a key. Which is a good thing. For EEPC McAfee tracks licenses based on how many you have vs. how many you own. The ePO server allows for unlimited number of EEPC endpoints. What you do need to keep up on is the number of licenses you purchase.
If you go into ePO, under Menu -> Software -> Licensing this will show you the number of licenses you have in use. Just make sure you purchase the same amount and you're set. No need to enter any license keys or serial numbers.
In response to your second question, refer back to the first answer. Since there's no key or serial to enter, there's nothing to expire.
Just be sure to keep up on the licensing and renewals and you'll be set. Otherwise you might get a nasty-gram from McAfee Legal
Thanks for your reply but you mean to say that there is no mechanism to monitor the number of users licenses for EEPC. If we purchase a license of 50 users and add 100 users then it won't stop us to do so or give us an error of license exceeded or something?
If we just renew the licenses of ePO and never go ahead with renewing the licenses of EEPC won't it stop us from using the EEPC and encrypting new devices?
The licences are monitored, but we do not (at the moment) enforce count - we trust our customers to pay for what they use promptly, and accurately.
When you "Renew" you are not re-buying the software - you are buying the right for content, upgrades and technical support.
BUT, if you install more copies of EEPC than you paid for, there's no other way of saying it other than you are pirating software. In the USA that means up to 5 years in prison and $250,000 fine http://en.wikipedia.org/wiki/Copyright_infringement_of_software
I highly recommend performing a count each year during renewal time. If you have any growth, you'll want to true-up with McAfee to make sure you are in compliance.