I'm considering doing some wiring myself. As I poke around the
innards of my house I've found various examples of previous homeowner
wiring that doesn't meet code. I haven't seen anything dangerous, but
it wouldn't have passed an inspection had one been sought.

I'm sure many old homes must have things like this. My question is
what happens if I call for an inspection to look at work *I've* done,
but this inspection will bring the inspector within view of work that
was done before I bought the house that isn't quite right (e.g. an NM
cable strung across an attic space instead of being stapled to
joists). Will that inspector require everything old they find that
isn't up to code to be fixed before they approve of the new work?

I know this may vary from place to place but wondered what general
thoughts were.