My understanding is that the expiration is more a factor of transponder battery life than anything else.
I'm assuming that's the case, because none of the E-ZPass transponders in my part of the country expire.
That being said, I was pleasantly surprised by the condition of the Illinois Tollway system when on it today. Highway-speed toll lanes and pavement was in excellent condition. Compare that to what we have in the northeast (cough...NYSTA and MassDOT...cough) and I actually don't mind paying the toll as much as I do in New York.
What's ironic is that the Tollway here used to be the system of highways out of date and in poor condition. However, in the past 10-15 years, that really has changed and they really are the best highways in Illinois, definitely much better than anything maintained by IDOT. The Tollway portion of I-90 in particular is quite nice now. Having driven on a number of the Toll Roads in the NE, I must agree that it is rather amazing they're not in better shape there considering how high the tolls are.
After Blago and the toll board being all but cleaned out by Lisa Madigan (the one good thing she might have done in this area) and Quinn the tollway itself cleaned up it's act. The biggest thing it did was distant itself away from Springfield money and politics and really just focused on having a clean image and what was best for the surrounding communities.
It also took a heavy approach in build for the future and not just the repair and replace system that it had in place for so many years, including looking at long term pavement options, green tech, proper water drainage and 21st century technology to help improve the roads and communities. This combined with actually improving the roadway itself via expansion and proper interchange relief has really changed the image of the Illinois Tollway itself. I'm sure there are still a few shady dealings going on underneath it all, because face it we are Illinois but overall the turnaround that it has put itself through and results are well worth it.