Originally Posted by
MSPeconomist
Hertz seems to charge extra hours IME, although after a couple extra hours it would be more than an extra day, so that the extra day is charged.
Also, if you do the rental reservation through AmEx PTS, there's an additional grace period, one or four hours in total. This can be very useful, although of course you need to compare the rates carefully as their agency rates might be more than you can get by calling Hertz or using their website for the booking.
If you have an AMEX Platinum, you always get the four hours if you book on the Hertz website, even if you don't use your AMEX to pay for the rental, you just have to use the AMEX CDP.