Plan One To Throw Away

Fred Brooks wrote a fun book about software development in 1975 called The Mythical Man Month. Brooks' ideas are remarkably fresh today:

Where a new system concept or new technology is used, one has to build a system to throw away, for even the best planning is not so omniscient as to get it right the first time. Hence plan to throw one away; you will, anyhow.

The Mythical Man Month, p. 117

The second system can be built bit by bit by replacing components gradually, or by starting afresh with a completely new architecture.