Everything that GegärterSiorenato23 writes is also true. I have never had any failures, even when I used the PT strips for a whole year after the expiry date. I then simply set the device date back by 1 to 2 years.
The expiry date is printed on the packaging. After receipt, the shelf life should be several months to over a year. Each pack comes with a code chip that is inserted into the device. This means that the device knows the exact expiry date and refuses to overrun the application. You could trick the device by faking a later date in the basic settings. On two occasions I have experienced a failure even before the expiry date. In both cases, I was told that there was not enough blood. The pipette then had to be filled beyond the line. I had probably stored the measuring strips at too high a summer temperature.