There is another factor that hasn't been
mentioned here. That is the history of your relationship with the contractor. if you have worked with the same yard for several years, always paid your bills on time, without question because you have learned to trust their work, then they will have also learned to trust you when they present their bill. I have customers for whom I have worked for twenty-five years,I have keys to their house. They call, I work, they pay. I haven't written a contract for those people for many years. There are people for whom I work that I have never before met , they saw my ads in the paper and called me. For them I write a contrat that details how many nails in each stick, how much and what color and brand of paint , clean-up, trash removal and PAYMENT. If it is a long job I get paid at the end of each week. If I don't get a check at the end of the first week I pack my tools and tell them I will be back when I get paid.