I suppose we're not "traditional" in this sense, but at Facebook we do somewhat more in-depth code reviews than just spot checking. Generally if you're modifyi

I suppose we're not "traditional" in this sense, but at Facebook we do somewhat more in-depth code reviews than just spot checking. Generally if you're modifying an existing system, you get one or two people who're familiar with that system (and thus know the big picture of code design, layout, etc) to review your diff. If you're writing something totally new, you usually throw ideas and mocks (either UI or code-structure) until you decide on a solution that works. I've found this to be pretty good at helping newer engineers write good (and idiomatic) code without hindering development speed much.