Just a thought - to clarify:
The Reader behaves in the way we've already posted.posted, but the main working part of the Libre system is the small
sensor that attaches to you arm (or other area of the body) and this IS definitely time limited, collecting data over a fortnight, after which time it must be replaced. In addition the sensor only holds its recorded data for the current 8 hours after which it's deleted, so it must be scanned into the Reader - at any frequency you choose - within this current 8 hour period.