I was wrong. They're not rules!
In the original writings I did about XP, I often referred to things like Pair Programming as “rules”. My recollection is that the whole C3 team referred to them as rules.
We also had a rule: “They’re just rules.”
Now even on the old C3 pages on XProgramming, they are called practices, but somehow, and I’m sure it’s my fault, the word “rules” entered the XP vocabulary.
They’re not rules, OK? They’re techniques. They’re tools we apply. They’re habits. They’re practices – things we practice.
They’re not rules, OK? You don’t have to do them, any more than you have to use a hammer or a screwdriver. It’s really good, before repairing something, to know how to use a hammer and a screwdriver well, and it’s really good not to try to fix everything with just one of those tools – or even both.
They’re not rules. They are, however, darn good things to know how to do, and do well.
You may now return to whatever you were doing.