We build these things from scratch because of all the lessons we learned (mostly about not building them from scratch) the last time we built them from scratch. :)
Definitely true, most of what I've learned building stuff from scratch has been about not building stuff from scratch.
For my own projects I generally think YA(aren't)GNI that original feature, but YA(re)GN(or at least want)I that framework instead of vanilla, or that declarative config tool, or those type Annotations, etc.
