You will typically pay for a pay-per-mile policy monthly, since rates are not fixed and will change according to your monthly miles driven. Although each company sets its own guidelines, paying in full for the policy period is likely not an option if you choose pay-per-mile insurance. If you have the option to pay in full for the policy period, your monthly amount due will decrease the unused credit amount to pay your premium. At the end of the policy period, you may have to pay more if you drive more miles than anticipated, or receive a refund if you drive less than expected.