No. It’s very nice, but for things like actual electrical and gas work, a permit is required.
Many people don’t pull permits however - it’s something to be aware of when buying older homes. The advent of arc breakers and GFCI have reduced the chance of serious harm in these areas.
And I’ve also seen (and done) work that was significantly above the base line contractor level (that nobody would pay for usually) just because it was the homeowner bothering to do things very right.
