What happens if an engineer comes up with a way to build a safer car door? Can that new door be deployed right away? No. A stamping machine and a custom made die produce that door. Together they cost over 10 million US dollars and they must first be amortized before the new door can be economically produced. Given the high costs, it can take 10 years or more before that better door can enter production. You can see the impact of the need to amortize huge investments in the slow, incremental changes in automobiles from year to year, even from decade to decade!
WIKISPEED can change their design every seven days. They employ tools like value stream mapping not merely to reduce the variance of products produced or to optimize the flow through the production line, but first and foremost to reduce the cost of change. It does not cost them more to use a new design than to use an existing design. So if they have a safer way to build the door today, they start using it next week.
Welcoming and responding to change represent core Agile values and principles (see the Agile Manifesto and the Principles behind the Agile Manifesto). So by adopting this principle, you take a huge step towards becoming an Agile organization.
Tomorrow: Object-Oriented, Modular Architecture