Lean waiver after work?

[Ramon Mota]

We have a contractor in North California that just completed a roof for us. We had one little thing they are going to fix today and receive the final payment. I would like to say that this roofing company is heritage roofing in dunsmuir CA. They stuck to the bid, completed the work in the time frame described, and worked with me to fix issues found once the roof was off. So I would recommend them. Should I have them sign anything like a lean waiver or something stating they have been paid in full for the completed work? Any advice would help. I have had good interaction with them so I don't see a problem but just making sure.