Just like bridges, every software application is different. Imagine a construction company saved money by not making detailed blueprints for a high-rise building. Instead, they gave their electricians documents explaining how the future occupants wanted to use each room in the building. Would you feel safe in that building?
That approach sounds absurd; however, that is how most of the software industry operates. Many teams have user stories and flowcharts, yet they still need a meeting to do the equivalent of determining what circuit breaker controls an outlet.
At the start of a software project, a team can answer questions quickly due to having extensive knowledge of the project in their short-term memory. Over time, people move on to other projects or forget some implementation details; gradually, it becomes more expensive to maintain and add new features to even a small project.
SOFSAFE's software blueprint procedure solves this issue by specifying what must be documented for database fields, method arguments, instance variables, and other vital details. Unlike code comments, updating the software blueprint can be done by anyone on the team and doesn't require re-running automated and manual tests due to making a git commit that fixes a typo in a comment. Documentation can be improved over time by the entire team, enabling engineers who are new to a team to make reliable production changes much quicker.