How many fantasy novels have Our Heroine travel a dangerous path, only to have an old wise woman give them the Sacred Amulet, the Ancient Book, or some other relic of the olden days that can save civilization’s bacon in the knick of time, right here in the present?
Well, knowledge in the real world can be like that, too! We get so wrapped up in the new-hot-thing that older, traditional methods go out of fashion. The trick is not to let that old, hard-won knowledge go to waste.
I find the ancient kinds of knowledge particularly fascinating. Did you know that doorknobs used to be brass because copper and copper alloys kill germs? And that hospitals that use copper for their frequently-touched objects have lower rates of infection? That even now, some parts of India purify water by storing them in brass vessels?
Ancient knowledge can protect you in a calamity, as well. There are stories that some villagers escaped the 2004 tsunami thanks to the oral histories that had been passed down.
How about technological threats like cyber warfare? Well, the Navy is once again teaching navigation by sextant, so that if newer navigation goes offline, their ships will still be functional.
Like the song says, Everything Old is New Again.