Or, I could be just making it up.
But one thing I have noticed is that there's a definite bias toward looking at software three times.
I worked (briefly) with an agile project management group that suggested that everything will be released three times, called the "Good", "Better", "Best" releases.
- The good release passed the unit tests.
- The better release included any non-functional (performance, auditability, maintainability, etc.) improvements required.
- The best implementation possible.
Not everything required three releases. Simpler components can merge better and best. Some components simply start out in really, really good shape.
What I've also noticed is that the explanation of the component -- writing documentation, presenting to peers in a walkthrough -- leads to profound rethinking.
May things may appear to be better or best in the sense above. Until we have to explain them. Then they're no longer "best" but merely "better" or perhaps even "good."
A few minutes spent hand-waving through a design often points to things that aren't quite to easy to explain. A walkthrough is very beneficial to the person doing the presentation.
But, not too early.
When I made military software, we had Preliminary Design Reviews that were done before coding begins. The idea was to surround the difficult coding work with yet more process steps and yet more deliverable intermediate results.
The intent was noble: if a walkthrough reveals so much, then do the walkthroughs early and often.
However. I'm beginning to think that early isn't ideal.
I think that the design walkthrough should be delayed until after minimally working code exists. Once there's code -- with automated unit tests -- then refactoring to meet non-functional quality factors (like performance) is easier and more likely to be successful.
Also, refactoring to make the software clear, simple, and elegant should probably wait until it works and has a complete suite of automated unit tests.