And see, that's the weird thing - I KNOW mine isn't from heat damage, because I've never used direct heat on the head of hair I currently have.
I don't have any color left, so it's not chemical damage.
It could be stress from using seamed combs, but it'll be a couple of years before I can prove or disprove that.
I'd suspect it's not from the natural kinks in my hair, as the relaxed ladies are getting the same thing.
*thinks*
My hair isn't long enough to ponytail or bun, so it's not repeated stress from that.
I rarely use hair toys/bobby pins/elastics, so I doubt it's from that, either.
I really don't know.