Call credit from Lebara (Lebara One and 10 = 20) has no expiration date. Keep in mind that you must use your SIM at least once every 90 days to keep it active. Prepaid data plans are valid for 30 days, except for the 500MB plan. This plan is valid for 28 days. All All in NL and All in International plans are also valid for 30 days.
All Sim Only bundles (2GB, 5GB, 7GB and 10GB) are valid for 1 month.