Chapter 2 - A tale of two values

Two different values
1. Behaviour - what the code does, correctness
2. Structure - How easy the code is to change
Many programmers believe that their job is to focus on behaviour and neglect structure
The difficulty of making a change should be proportional to the scope of the change, and not to the shape of the change
- Proportional to the change to the domain model
Developers are given a stream of changes which pull the code in different directions
Code designed for one day's changes may not easily fit the next's
Architecture should be as shape agnostic as practical

The greater value

Structure is more important than behaviour
Good structure makes the code easier to change
- Poor behaviour can easily be fixed
Poor structure with good behaviour will have poor behaviour when the requirements change
- And will be hard to correct

Priority
1. Urgent and important
2. Important but not urgent
3. Urgent but not important
4. Neither urgent or important
Architecture of the code is important
Behaviour of the code is urgent
Do not prioritise behaviour which is urgent but not important over important architecture
Business managers are not trained to understand the importance of good architecture - not their job
- Responsibility of the software team