It all depends. Some have to have then all the time and some don't. I had one (an emergency one at that) and because the way the doctor cut me on the inside I have to have a c-section for every pregnancy I have. And how they cut me I have to have my baby at 30 weeks. I can't go the full 40 weeks or my uterus will explode from expending to far.
I'm going in for my 3rd in May and doc recommends I get my tubes tied. But it could also be bc I'm in my 30's.