Subclassing XP: breaking its rules the right way

Extreme programming encourages adoption of all of its practices. In practice many projects drop practices. What remains can be an incomplete methodology, which is dangerous. This problem can be overcome by replacing each removed dropped practice with a compensating practice tailored to the circumstances of the project - effectively subclassing XP. This experience report recounts the experiences of subclassing of XP at Wotif.com, where pair programming was replaced with "pairing" and refactoring was replaced with "team refactoring".