All good points bulldogger. In the case where someone maybe new to the hobby, I think it serves them well in the long run to hire a local HT installer the first time. If the right person is hired they will make sure that the layout is done for future considerations, along with being right the first time. But that doesn't mean you close the door and say go to work. I would want the installer to explain what they are doing and why, so that I am learning along the way. I used a local person the first time and volunteered to be his second hand...saved money that way, since it was a two person job. I learned every step of the process, so when it was time to redo the work for another upgrade....I did the work myself.
Ron