My DS has always had some sort of an obsession with my hair. He would just yank and yank and yank on it and pull it out in huge gobs.
Starting around 8 months of age, I resigned myself to the fact that there is apparently no replacement for mama's hair (and, it really is cute that the little guy is so attached to my hair) and started working with him. I really had to work with him to show him how to keep his hands soft, not pull, but he really learned pretty quickly. It just took a few weeks.
Now he won't go to sleep (if he's with me) without playing with my hair. And in the middle of the night he'll reach up and play with it.
He does the strumming like a guitar thing sometimes, but anymore he doesn't usually pull it hard when doing that so I let him.
So, I think it depends on how much your various DC like playing with hair. My DS did it constantly and I'm glad I taught him to play nice with it (although sometimes he forgets). My DH has long hair but he didn't like DS to mess with it, so he has taught him not to mess with his hair and been very successful by just removing his hands from it and telling him now.
Don't know if this helps anyone, but I just thought I would share my experience. I think it's really cute how much he likes my hair.