Often you'll see the same three or four data items together in lots of places: fields in a couple of classes, parameters in many method signatures. B… - Kent Beck

Refactoring (noun) : a change made to the internal structure of software to make it easier to understand and cheaper to modify without changing the observable behavior of the software. To refactor (verb) : to restructure software by applying a series of refactorings without changing the observable behavior of the software.

The key is to test the areas that you are most worried about going wrong. That way you get the most benefit for your testing effort. It is better to write and run incomplete tests than not to run complete tests

The new concept of Extreme Programming (XP) is gaining more and more acceptance, partially because it is controversial, but primarily because it is particularly well-suited to help the small software development team succeed... XP is controversial, many software development sacred cows don't make the cut in XP; it forces practitioners to take a fresh look at how software is developed.