I believe strongly in personal rules. If we learn some sort of life lesson along the lines of "I will never do that again" or "I have to make sure I do that again", and we came to those conclusions during a moment of clarity, then we should stick to those convictions.
People who do not follow their own rules are weak-willed. But people who never revisit their rules are blind fools.
If you ever feel like you want to do something that you strongly feel you shouldn't, you need to ask why, and you need to ask about both sides. Why do you want to break your rule? Why do you think your rule should be followed? What is the rule intended to do, and is that really a good thing?
I really want to stress here that the advice is to revisit your rules. That is distinctly different from changing your rules. Revisiting simply means that you are looking at the rules again. You may conclude that it is still a good rule, or you may find it is out of date. In the latter case, that may lead you to changing your rules, but revisiting never requires it.
This is the approach I take with my writing. What do I believe? What do I never want to do? What do I think I shouldn't do? And what is my hangup with it? If I don't have good answers, then I change my beliefs.