For the second point you're are addressing, time (at least at a human scale) doesn't meaningfully help in the determination since the sample size is a single unit - your personal EMT shears. I have a 30 year old knife that works great and hasn't been sharpened since I got it. I also have a 3 month old knife that has been sharpened three times. No meaningful conclusions can be drawn from either or both of those samples.

It is impractical for a single person to try to master all the available and potentially useful skills that humanity has identified and refined over the years. We live in communities for a reason.

Based on the above I'd say your second point was also made (or should have been obvious to the proverbial "casual observer") three years ago.

That does not invalidate key point I think people were driving at. You need to have a plan that works for you on the day your shears are no longer meeting your needs since nothing material lasts forever.

Having said the above - I'll fess up that I am terrible at tasks that require fine motor skills (like knife sharpening) but have gotten, uhm ... competent(?) at the ones I find important by leveraging tools and technology but everyone needs to chart their own course.

-Eric