The meta-framework
There is one aspect that is often overlooked when working with an established code base. The meta-framework. The code base for a certain application can consist of many frameworks. For example, Spring, Hibernate + Velocity. However the way these frameworks are used, the internal conventions even the domain model if one exits, plus the other pieces of the puzzle like the build, the deployment process, the testing process, etc make up what I think is a meta-framework. Familiarity with all of these pieces, allows one after some time to be able to get a good level of confidence in doing something that is key to the longevity of an application and your value. Estimation of new work.
It is also possible, to some degree, to re-use these meta-framework pieces and use them on new applications. What is often lacking is a good starting point. So much so that I would bet most teams just start from scratch for each new project while still using pretty much the same pieces.
If one can find a way to re-use this meta-framework and apply it to different applications, then re-usability is achieved, and the ability to predict time and costs for particular projects becomes less of a variant.
