I am scheduled for my first sew-in tomorrow so I don't yet have personal experience. My hair is thin and fine though, so the plan is to braid the cornrows with extensions to give the tracks a firmer base and take some stress off of my own hair. This was the recommendation of the stylist. I think the important thing if your hair is fine, it to use a soft high-quality human hair for the braids because (at least for me) the coarse synthetic stuff chews up my natural hair. Good luck!