So rope and biner ratings are of no value?
Replace expiration date with any other certification, test result, or rating.
I’m not saying they aren’t useful for performing calculations(as in math). I’m saying they’re useless, and downright dangerous when included in risk assessment as a mental exercise. They are arbitrary values, generated from related, but not exact processes to what you may encounter personally.
Humans suck at big numbers, probabilities, and statistics. Reliably. The only way to make them worse at it, is to give them actual numbers to play with in their back of envelope thinking.
What I’m saying is Unless you’re really good at the math involved in calculating risk, which likely involves significant training, “doing what everyone else is doing” is no more risky than you guessing, based on some numbers on the side of a carabiner, what to do. In fact, you’re probably at less risk of a significant failure or injury by doing what most other people are doing, rather than thinking you guess your way through it because of a stamped date or value.
My point all along with this concept has not been “do what everyone else is doing.” Or “ignore warnings, ratings, and guidelines.” I’m saying doing that is less dangerous than pretending you’re good at math.
The best thing to do is to recognize that the risk of leaving the ground, compared to not leaving the ground, is so much higher, that any precautions you take in doing so are statistically irrelevant. Once you accept that, it grounds your expectations properly, and you can work through the math with the proper framework.