As the issuer of a voucher you are obligated to redeem it within its period of validity.

If the voucher is valid for more than 3 years, the issuer can use the voucher again for payment.
If the validity period is shorter than 3 years, the issuer destroys the voucher after redemption. Due to this rule, participants of the network practically rarely receive vouchers that are about to expire.

If you are a guarantor of a Minuto voucher you are only obligated to redeem it if the issuer and his legal successors (heirs) are unable to provide a service, for example in the event of: Inability to work or earn, “address unknown” or death.