The present invention relates to an electronic purse data carrier for performing monetary transactions and a method for managing electronic payments with such a carrier. The purse stores one or more payment units each having a respective monetary value, whereby each of said payment units has a respective unique payment unit-ID and comprises an age information evaluable for delimiting the use of it. In particular said information defines a dynamically changing age level. This can be used to force purse owners to return each electronic monetary unit back to the issuing party after a specified cycle measured in time or transactions has passed in order to validate the authenticy, and in particular in order to test for possibly duplicated monetary units.