I too would be a little cautious of someone leaving a note, unless of course you contact him and ask him to come and give you an estimate then you can ask him about what he is talking about and so on. Have him show you what he is referring to and ask him for references to check out. If you can see work he has performed that is even better.

I would like to the thank the person that left the link to the DIY as this is good information to know.