i have two great guests, extremely knowledgeable folks, anthony wong who is a contractor here in the city, thanks for joining us, anthony. and dan, also a contractor and both of these gentlemen do a lot of small, medium and some, i guess you do some large size jobs as well. but also have maintenance and home prevention, damage prevention and maintenance issues built into the work they do. in fact, i know dan brought along a list of maintenance check lists that they actually use in their business to help people. so what do you use that mapet nance check list for? -- maintenance check list for? >> for every project we finish, we sign a service agreement or offer a service maintenance agreement and then when we go back to the house a year later we go through this check list and we go through the whole thing to make sure everything's being maintained, that, well, it's a very detailed check list. but every house in san francisco needs to be maintained and you can see through lawrence's slides what happens if you don't maintain them. >> in my experience, often people do wonderful design wor