Why Late Payment Clauses Work Clear consequences for late payment reduce payment delays by 60% according to freelancer surveys. Effective Clause Structure Grace period (5-7 days) Late fee percentage (1.5% per month) Interest accrual terms Right to suspend work Collection cost recovery Sample Language "Invoices unpaid after 30 days incur a late fee of 1.5% per month. Client agrees to reimburse all collection costs including reasonable attorney fees."