In addition to what's already been stated, depending on the area being serviced, I require a nonrefundable deposit for service. The deposit is settled at the end of the contract allowing immediate payment for the first snow or chemical spread. usually this is absorbed in the first chemical spread as being "free" spreading the first time out with a charge for the material used. This also depends on the amount you require for a deposit. Generally, I require an amount equal to the lowestsnow depth that they expect you out on. (2", or 3", or whatever)