Do it right and only do it once. I tend to go a bit big on wiring, larger gauge if I can. Follow the codes, even if you aren't getting inspected. As stated above, it SHOULD (in theory) make things safer...altho some of the codes I've seen as of late make me question that. UL is just a for profit company that has convinced everyone they make things safer. I've dealt with them for may years in a previous job, and mostly it was hittting a threshold of money input on a design to get the rating....and some of the things they wanted, well, just lets the stupid people be stupid and not cleanse the gene pool...design for the lowest level of intelligence and then make it even more dumber. In my new shed I put batt on the walls (2x6) and blew in the cieling (what a fun way to spend a day) for R38. Do what you need to do for your area to keep the hot/cold in/out and move on. Just make sure not to block the eaves for the soffit ventilation.
I've run across it all over my years building and helping others:
use of an extension cord in a wall instead of ROMEX
3 taps in a breaker box off a breaker
hot/neutral switched
running hot thru a ground
unsupported load bearing areas
caulk used to seal a drain line hole or joint
duct tape on bare wires
jbox on a wall with live bare wires hanging out
3 wires tapped onto a screw on outlets
breakers "forced" to not trip
ungrounded conduit
tapping 110 off 220
every screw/nail under the sun to put a wall/sheetrock up
the list never ends.....