How do you stop headphone cables from breaking at hard points?

You can't. It's called wear and tear. The manufacturers, OEM suppliers and after market suppliers love it.

What you can do tho, is use suitable heat when soldering the plug. Too low it'll break at the terminal, too hot it'll break after the terminal. Shrink around that, too.

I seen a dude here mention he uses the spring from a ballpoint pen for strain relief, I thought that was really clever. It does allow movement tho.... and where there's the movement, there's gonna be a breakage eventually.

I personally (I am rough as fuck with my gear and use it in industry), I use a glue lined heatshrink and put that around, as strain relief. I get that glue really hot, that way it goes hard and not rubbery. I run that about 10mm past the strain relief, gland. That's how I've been doing it for a few years now, and I haven't had a break after a plug in months. I'll show you. It's abit rough, but it works. And push the cable right in, before the glue sets, that gives it abit more give. Think about it, you pull on the "cable", but by doing this, your actually just stretching the pvc insulator and not the actual wire.

Here, check it out See the glue spewing out of it? Yeah, like that. Keeps it all firm in there.

/r/headphones Thread