Learn the money side before the spade goes in

Most self build money is lost on paper, not on site: a quote that was never complete, a contract signed unread, changes agreed on a handshake. By the time those lessons teach themselves, the money has gone. Time spent understanding how builders price, what a contract does when something changes, and why payments should follow work rather than dates costs you nothing and changes how every later conversation goes. The builder does this every month; you are doing it once, and closing that gap before anything is committed is the highest-return hour on the whole project.