the various inspectors loooooooove to tell you what's not to code, that's for sure... not that I would be guilty, however
the best way to know the codes is to either purchase them (usually premium bucks, but necessary if you do it for a living) or find out from the tradesmen themselves (which alot of them don't like to reveal, after all they make their money providing the service, not teaching people how to do it). The various municipalities find themselves in the interesting position of homeowner/DIY'ers pulling the permits to do their own work... which I think is nuts! How can you expect the average homeowner to understand what they're taking on? But rules are rules, if you own the place you get to do it all! So I suggest you to research your local rules to the best of your abilities through your city hall so you can avoid the headache and pocketbook-ache of having the project fail inspections due to lack of knowledge.
Here's the line I draw: doing reno and feel up to making some mistakes as well as progress and have some time? go for it! taking on an unsavoury project that needs to be done in a reasonable time and requires permits? hire tradesmen!