A few weeks ago it was beginning to get dry here. I had a customer whose smallish front lawn was starting to show some stress. I skipped a mowing and they agreed that I could put out a couple sprinklers and give the lawn a drink. The next week I mow and in addition to the regular bill I include a small additional bill for laying out my hoses and sprinklers and then coming back later in the day and picking them up. Customer pays the regular bill but not the add on. A week goes by and in the meantime we start getting meaningful rain. I again cut the lawn and rebill the watering charge. So... a few days later I receive the customer's check for both the mowing and the watering and a note telling me to hold off on any additional watering. This is after the area has had several rainfalls which would make additional watering ridiculous. What am I missing?