There is something I should have made a bit clearer. An auction ends when the other parties give in, and who has the highest bid will hire the driver. So really, as long as people keep making bids, an auction could even last a couple of months… Just depends.
To win a driver auction you need to have made the highest bid on the driver. A full week with no other bidders bidding higher needs to pass before a team can sign a driver. Of that makes sense.
Also if a driver has been bidded on , and then the driver moves up in the WDC, all bidders must match the new price.