There are two separate agreements:The salary sacrifice agreement is between the employer and employee and covers the repayment of the voucher cost.  This can be for any period longer than three months that both parties are happy with.  Common terms are 12, 18, 24 months but it could be for as long as 60 months.The hire agreement is between the employee and GCI Ltd.  This is unaffected by the length of the salary sacrifice.