I've been cooking dry beans for years and I've always ignored the directions to carefully pick through the beans for debris.

This pebble was detected, thankfully, by my tongue and not my teeth.

oooof glad you didn’t chip a tooth on that

i never pick through mine but maybe I should start.

I like my rocks Al dente

I've never washed beans or rice before cooking, but every source I can find says, yes, you should. Besides potential rocks (which I have never seen) there are also "anti-nutrients" that get washed off and it's supposed to taste better, too.

At least put them in a colander, in a bowl of water or a stream of running water, and rub them around with your fingers to feel for pebbles. Gets the dust off too. Then use fresh water for cooking.

soaking beans also helps remove farty oligosaccharides, which is why i soak them even though i have a pressure cooker

soaking them in salt water also makes the skins break less (i learned that the idea that they won't cook if they're salted is a myth. acid does prevent them from cooking though)