This has already been touched on but over the years I have learned to never do work without a contract. No matter what the amount is you must always have a detailed written contract. Also, when any changes and I do mean any you must make the customer sign a change work order. We have a detailed three page contract and will not do any work without a signature and other info. It also weeds out any problem customers or people that just want to rip you off. Good luck!    JT