I was stretching 12-14 or 16 weeks. But I found the last few weeks my hair would consistently start shedding 3 to 4 times more than usual. None of my protein treatments would curb it. So last time I decided to cut it down to 10 weeks and the shedding stopped. I think I'll keep doing this at least for the time being and hope my mild relaxer doesn't overprocess me. As it is, my hair doesn't relax straight-straight, so I think I'll be ok. If not, I'll go back to stretching longer. I just figure it defeats the purpose of stretching if I lose too much hair. My hair may get longer, but my ends will be thinner. I have to find the balance.