My final inspector is me. I will not do what I won’t for myself. My name is signed and dated on every installation. I abhor half-a**ed installs. I take each one as a legacy, of sorts. Those who can, do; those who cannot, supervise...or inspect.
As for why Chicagoland requires copper......kickbacks? Pex, wirsbo, any other number of nearly perpetual water conduits save time, resources, money and future headaches. Eventually, they will develope a viable and inexpensive alternative to copper linesets. As long as pinheads don’t kill the innovators in uterus.
Same here. I tell my customers that I build it like I would for my self, my family or my dearest friend. Have a good one.