Is it true in the state of IL you have to have at least a journeymans lic to to do something so minor as wrap teflon tape around pipe threads on a paid job?
If one hangs around this forum for awhile, you will encounter many widely different local codes. I think one has to remember that even the requirements that seem to many of us a needless or even stupid, are intended to keep the population safe. There are many instances of a DIYer asking if what he is trying to do is acceptable when it would be very unsatisfactory under any code. Then there are the ones who apparently feel than since they have no intention of having there work inspected, codes do not apply. There is a thread on the forum showing some of the unbelievable hack plumbing jobs encountered by some of the professional members. As a committed DIYer myself, I have learned a great deal from the many real pros that respond to DIY questions. One of the most valuable things is, I don't know nearly as much as I thought I did. It's somewhat like a young man learning that his dad isn't nearly as dumb now as he was a few years ago when he was a teenager.
It is also a case, as I tell my customers, of stopping about 2 minutes before you reach your level of incompetence. Go beyond that point and you will probably turn a simple job into a minor, or major, remodel. And as I told my neighbor last week after he reached that level and he told me that he had intended to cut the pipe off. "You stopped just in time. Cutting the pipe would have been BAD. Not cutting it was GOOD"