I recently heard a gentleman who was acting as his own builder say something that gave me pause. He said the company he hired to help him be his own builder told him the city or county building inspector is his quality control department.
Every single time I have followed the inspector through a house that's just been framed, I can find a handful of small discrepancies that the building inspector missed. It's not that he didn't know what he was doing—it's that there are so many variables and rules and every house is so different. He has to inspect a certain number of houses every day, and there's no way he's going to catch everything.
If you're going to be your own builder, it's time to read up on the International Residential Code. The framer should have a pretty good handle on it, but here in Oklahoma, a framing contractor isn't required to have a license or any kind of certification. It's up to you to be the backstop if you don't have a professional builder standing behind you.
Even more frightening, many parts of the state of Oklahoma don't even require building permits or inspections. Currently, the state adheres to the 2009 version of the International Residential Code. Even if there's no building department where you're building, you're legally required to adhere to that code. Don't hire any contractor who tells you differently.
The bottom line is that your builder is your last line of defense in quality control, which includes conformance to building codes. The contractors will make mistakes, some you'll see and some you won't, and your builder's job is to catch and fix them. If you're acting as your own builder, it's time to go to school on the International Residential Code (IRC) and be ready to catch mistakes you never knew existed.