This article focuses on the Home Portal licensing model, there are no limitations to licensing in Client or Vendor Portals.
Named licenses are considered standard in XTRF. They will always let you log into the system.
Floating license, on the other hand, means there are more users than free slots available for login. Floating licenses are usually offered to bigger teams spread around the world - once users form one time zone log out, users in another time zone can log in using the licenses that were just freed up by the first ones.
You may also consider setting time outs for your teams to make sure they are logged out automatically, when they forget to do so manually at the end of the day. The setting is called: Max. wait time before floating license check-out (in minutes):
Talk to our Customer Success Department if you feel some floating licenses would be useful in your situation.
Customer support service by UserEcho