When the contract is printed at the gate (at most major Hertz airport locations in the U.S. & Canada). I can't speak for other countries or locations that don't do this since all my rentals are at major airports. Before this was done, it was a crapshoot. Sometimes the time I made the reservation for, sometimes they'd post date the time by up to a few hours from the time of the reservation, sometimes it was when it was recorded at the gate (even though I already had the contract from the car or from the office).