ISE has been around about a decade, basically just as long as UTD. AG and Achim got the GUE boot at basically the same time.
So you have a spectrum:
UTD - no renewals needed
GUE - "25 dives" on the honor system
ISE - pay me to evaluate you again
Wow this is a totally new perspective ... GUE is middle of the road, almost maintstream! ;-)