I am having a custom home built by a local home builder. Work is almost complete and I am required to pay a final draw after a CO is issued. All prior draws have been paid to the contractor in a timely manor, (within 3 days of request). I have not requested any documentation of payment of material suppliers, sub-contractors, or labor to this point. What should I ask my contractor to provide prior to making final payment to protect me form liens that may be filed after the work is complete?