As to home owner insurance, it paid off when we had the fire. I had wired it with a residential wiremans' license under 1978 electric code. So now we have a mix betwixt 1978 and current code. To get the old up to modern, (which is not necessary), about all that would need to be done is to put a bar on the breakers for two circuits running in a 12/3 cable.
All wires are #12,10, and 6. Nothing smaller. And yes, I have had to track down a couple loose neutrals.
For the GFI circuits, I am only using a max of 4 outlets now, though not specified in the code. No doubt experience would have told me that, but I went to mining coal, and am just now getting back to it. Its been "interesting".