This is my first summer offering irrigation repair, / maintenance. Before this year I would tell customers that i will fix a head, set times and other controller adjustments. but never add to or remove any heads or zones. I knew that you do have to know how to properly understand the amount of pressure and how it works in the system. I still don't know as much as I'd like but i read and studied a lot before jumping into this service. POINT is I was like you but don't guess or service something you are not trained in. pass it on to one who knows. We can't do everything for all customers.