I think for me one of the most challenging things I've even done is self contract building a house. On paper it doesn't seem like that difficult of a task, people build houses everyday and builders are doing it constantly. Being the one off though for all the contractors and trying to build a team as I went with the knowledge that the contractors knew I was just building one house was very problematic and so time consuming.

Having a good team or in this case good contractors was worth their additional cost as they just got in and got their part of it done. I think if you are trying to do anything moderately complicated or even decent size having a good team that can handle their specific tasks is so valuable. "Do your job", is the famous line Bill Belichick asks of his players and I think he has done pretty well with that concept.