I used to be PC but now FS. I'm usually in a National rental now. This week I'm in a Hertz weekly rental, first time in a long time. They have added a button that says "Extend Rental" to the app/webpage since the last time I rented with them. So I want to know if it works 100% of the time, if there are any traps I might fall into doing so, etc. For example, with Enterprise, you can extend it up to 4 weeks guaranteed, at the same exact rate guaranteed, no problem, never fails. Does it work that way with Hertz? What limits are there? Price changes etc? Tell me anything I should look out for. Next week is a cheap week (I could actually take it back in for $20 savings if they rewrite it) but the week after that is twice as expensive, and I'm going to need it that week too.