What's your policy on customer supplied materials?

Our work order clearly states that we guarantee our materials and labor for 12 months. Customer supplied materials and the labor needed to repair are covered by the manufacturers warranty only.

We won't even bid if the customer starts asking if they can supply all materials. It's usually a good indication that the customer is cheap! It's OK if they want to provide light fixtures(other than cans, under cabs., and puck lights), but when they want to buy the switches and cover plates or the wire nuts and boxes I walk away. Occasionally a customer will ask to break out 1 item, in that case I take out our cost, but leave the mark up in.

What do you do when the customer want to provide some labor? I had a customer that wanted to drill all of our holes. I tried to explain that it would take me longer to show him where to drill than for our guys to do it, but he insisted on a discount. I took off $30, he let us drill.