Each section has 'why not' and 'when should you', so really it's a "Do (only) when" recommendation. I don't see sufficient justification for "Don't use serial"

Each section has 'why not' and 'when should you', so really it's a "Do (only) when" recommendation. I don't see sufficient justification for "Don't use serial"--the some weird behaviors links to a 404 page. The "Don't use varchar(n) by default" reasoning is similarly weak. This post doesn't doesn't give enough detail reasoning to be self-evident, and other than the quality of formatting could be a collection of anyone's blog posts. Some recommendations seem to be solid, but mixed with the arbitrary ones loses some of its recommendation strength.