0. Always remember the source of the rule.

All through my life, especially my career, I have run into rules that make no sense.

Once I was given a 'beat down' by the IT department of a former employer for not following a specific rule. When I asked how I was to have known about the rule, they said it wasn't documented or published. I then asked if there is a list of other undocumented/secret rules I should know about. They didn't laugh.

Too many times a rule or guideline is drawn up and rolled out to the masses. Then time goes on, and if things are going well, the business changes. [Side note: If your company doesn't change, then get a new job, because that company won't be around for long.] After the change, the rule is still blindly followed, doesn't make any sense, and people are still following it.

Also, after this business change, the rule might need to be updated or removed entirely. If you don't remember the reason for the rule, then you won't know when it needs to be updated.

This following joke explains this better than I can. I have seen this come around about every two years, and it is always a good read.

The Origin Of Company Policy
Start with a cage containing five monkeys. Inside the cage, hang a banana on a string and place a set of stairs under it. Before long, a monkey will go to the stairs and start to climb towards the banana. As soon as he touches the stairs, spray all of the other monkeys with cold water. After a while, another monkey makes an attempt with the same result -- all the other monkeys are sprayed with cold water.

Pretty soon, when another monkey tries to climb the stairs, the other monkeys
will try to prevent it. Now, put away the cold water. Remove one monkey from the cage and
replace it with a new one. The new monkey sees the banana and wants to climb the stairs. To his surprise and horror, all of the other monkeys
attack him. After another attempt and attack, he knows that if he tries to climb the stairs, he will be assaulted.

Next, remove another of the original five monkeys and replace it with a new one. The newcomer goes to the stairs and is attacked. The previous
newcomer takes part in the punishment with enthusiasm! Likewise, replace a third original monkey with a new one, then a fourth, then the fifth.

Every time the newest monkey takes to the stairs, he is attacked. Most of the monkeys that are beating him have no idea why they were not
permitted to climb the stairs or why they are participating in the beating of the newest monkey.
After replacing all the original monkeys, none of the remaining monkeys have ever been sprayed with cold water. Nevertheless, no monkey ever again approaches the stairs to try for the banana. Why not? Because as far as they know that's the way it's always been done around here.

And that, my friends, is how company policy begins!

Rule 0: If you are going to make a rule, document the reason behind it, so that people will understand the rule, and know when it should be refactored or garbage collected.