This thread makes me think of my history in decompression diving.
Phase One: No computers. Plan and execute the dive using a bottom timer and Ratio Deco.
Phase Two: No computers. Plan the dive using deco software, making a written plan you intend to follow and two contingencies that you would use if they turned out to be closer to the reality of the dive.
Phase Three: Use the three plan method, but take a computer as backup.
Phase Four: Reverse Phase Three by following the computer and using the written plans as backup.
Phase Five: Two computers.
Comments on the history:
Phase One: when two friends on a team got bent, they were able to check the computer log of the one who used a computer in gauge mode. It showed that although they thought they had executed the dive perfectly, they had actually made several significant errors. Doing the math in their heads proved problematic, and one of them had a PhD in a math-related field.
Phase Two: A friend of mine related a story about a frightening experience in which circumstances put them in a far different situation than envisioned, and none of the contingencies were even close.
Phase Three: I only did this on dives in which I was tagging along with others using this method. At each stop, they did the stop as planned and then waited until the computer backup cleared them for the next level. After the dives, I asked whether they were actually following the written plan or the computer, and that led to a discussion.
Phase Four: That phase did not last long for me. I went to Phase Five pretty quickly. Once I realized that if I had decided that relying on a computer was the best choice for the primary source, then it must follow that I believed it was superior as a backup as well. Given the cost of everything else in tech, the cost of the second computer was not that big a deal.
