By default, a ticket is scannable once per scan service. However, some tickets are valid more than one day. You can configure this under advanced settings within the Scanning environment, where you can set the number of times a ticket may be scanned.
If you are working with an event of multiple days, we recommend you to set up a separate scan service per day and to make the ticket scannable once on both days. This prevents problems if a ticket is (accidentally) scanned twice on the first day.