If anything can go wrong, it will.
This is not just supposed to be a joke. It should be internalized. Once internalized, this question should be asked before completing a project: OK, now what do we do when something goes wrong? (because we know it will.) Engineering or planning is not complete until this question is answered.
The same is true of Curt's laws. They should be internalized, and then satisfied in the process of a project.
Curt's 1st Law
If it hasn't been tested, it doesn't work.
Remembering this idea should remind us to always test every aspect of a completed project. It may be that most things work, but there will invariably be found something in the system that still has a bug in it. This law applies whether one is installing equipment, writing a program, or writing a letter. We should always proof read our letters and correct the errors before sending them, say it better than we did at first, and remove what we should not say. A letter won't work if it doesn't accomplish its objective, or creates problems that we should have anticipated by how we said it.
Curt's Law on Safety
If we have to be careful, we aren't safe.
There is a story that illustrates this law. Once a boy was helping me work through a fence. I said, "see all of those wires sticking out, you could cut yourself on one of them." He said "ok, I will be careful". "No", I said, "we will bend all of those wires back so you don't have to be careful." The question to ask to satisfy this law is this: What do we need to do so that we are truly safe, and don't have to be careful.
Curt's Law on Redundancy
A system is not redundant until there are three each of every part.
We want our critical systems to be up and running 100% of the time, with zero down time. If something goes wrong in one system, it is no longer a redundant system. If something goes wrong in the second system, we are down, and fail to meet our 100% goal. So if one system goes down, we need to have all of the spare equipment and parts so that we can fix the down system very quickly to bring us back to redundancy. So redundancy really means we want at least one system working 100% of the time, and the second system working 99.9% of the time. We can't do that without spare parts.
Curt's Law on Assumptions
Never Assume Anything.
Whenever you say "I assumed" it is your fault that you got it wrong. To get things right you need to know the facts, and all of the facts. And you need to double check and find out what you missed. "Measure twice" (at least)." You need to know the facts before you do something, and assuming is not knowing.
Curt's Law on Communication
If you don't tell someone, they don't know
People need to read or hear things to know about them. A supervisor should say something rather than assume that people know it. There are costs to doing things without all of the information necessary to do it right. The higher the cost of getting things right, the less money left over to get paid.
Don't get upset if someone tells you something that you already know, or warns you about something that you are aware of. Some day they will warn you about something that will save you from an accident or a lot of grief. Be thankful that people care enough about you to say something when they don't know if you are aware of a danger or issue.