I use Borax and find it helpful. My water supply doesn't have chlorine in it. The boron reduces problems with mildew. It also allegedly softens the water, but I use baking soda as my primary water softener.

I also have successfully used Borax solution in cleaning of porous surfaces to eradicate mildew problems in areas that bleach doesn't work to eliminate long term.

Can second this. I use it in all my laundry in SF - drastically reduces mildew. I also dissolve it into the hot water I used in my carpet shampooer. I have an allergy to mold, and borax has proven to be extremely effective in reducing mold to tolerable levels.

I'm a millennial.

Under 50.

Used "Terro Ant Killer II", which is syrup that contains borax and works about as well as the original formula that contained arsenic.

Never used Borax (except as hand soap). But I have used this: http://mrsstewart.com Another throwback laundry product. (I was inspired to try it when I read they make new clothes look whiter by tinting them blue)

I don't know about new clothes, as bluing works because it's complementary to yellow, which usually means "used". https://en.m.wikipedia.org/wiki/Bluing_(fabric)

Also a key ingredient in growing crystals, if I remember my children chemistry experiments correctly.

I use borax pretty much every day in a biochem lab. 20 g of borax in 1 L of water works really well as a cheap buffer for DNA work.

But I had no idea it was (or how it would be used) for laundry.

Yes, I keep a box in the cupboard because it has lots of household uses apart from laundry. Cleans drains pretty well, good ant killer.

My wife uses borax to make our laundry detergent.