If you're afraid to change something it is clearly poorly designed.

In almost all cases, I’m opposed to setting aside time for refactoring. In my view refactoring is not an activity you set aside time to do. Refactoring is something you do all the time in little bursts.

One of the things I've been trying to do is look for simpler or rules underpinning good or bad design. I think one of the most valuable rules is avoid duplication. "Once and only once" is the Extreme Programming phrase.

A pattern is an idea that has been useful in one practical context and will probably be useful in others.

When you actually sit down to write some code, you learn things that you didn't get from thinking about them in modeling terms...there is a feedback process there that you can only really get at from executing some things and seeing what works

Comprehensiveness is the enemy of comprehensibility.

Comparing to another activity is useful if it helps you formulate questions, it's dangerous when you use it to justify answers.