"When you find you have to add a feature to a program, and the program's code is not structured in a convenient way to add the feature, first refactor the program to make it easy to add the feature, then add the feature."

“I always knew that one day Smalltalk would replace Java. I just didn't know it would be called Ruby.”

“The new concept of Extreme Programming 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.”

“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. Bunches of data that hang around together really ought to be made into their own object.”

“The business changes. The technology changes. The team changes. The team members change. The problem isn't change, per se, because change is going to happen; the problem, rather, is the inability to cope with change when it comes.”

“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”

“Optimism is an occupational hazard of programming: feedback is the treatment.”