I think that if you're using a well-developed framework, you can safely ignore #9. However, his advice is SPOT-FREAKING-ON for any home-grown stuff. The last

I think that if you're using a well-developed framework, you can safely ignore #9. However, his advice is SPOT-FREAKING-ON for any home-grown stuff. The last time I ran across a "core" directory, there was all kinds of application-specific code in there, all rolled up in switches and stuff - if you wanted to develop something using the "core", you had to go through about fifty files and add your own cases for your site. It was awful.