You've definately gotten some great advice in this thread. I have used the Crown and Glory method to get some serious growth.
Right now I'm bunning my braids, since my hair is long enough to rub against my clothes if I wear my braids down. Being braided offers some protection, but leaving the braids rubbing all over rough surfaces will still cause breakage. Some people get kinda lazy with this aspect when they are in braids, and it's not good for length retention. I still sleep with my satin bonnet on, and I also put a satin pillowcase on my pillow.
You mentioned that you are concerned about getting breakage while detangling. Wearing your hair in braids keeps the hair from getting tangled to begin with, in my experience. As long as your hair is combed through well while it is being braided, it stays that way till you take your braids down.
Another tip for healthy braids... when your hair is braided, some people divide the natural hair into 3 sections, and each strand of the braid contains natural hair and added hair (Kanekalon, etc). I used to do my braids like that, but I find that it makes takedown more difficult and can lead to tangling and breakage.
Now I attach the braid hair, and let my natural hair be the third strand all the way down till the last inch or so of my real hair. Only at that time do I "borrow" some hair from the two strands of synthetic hair and sandwich the false hair on either side of my ends. This becomes the third strand which I braid down either till the end (Kanekalon braids) or for an inch or so past my real hair and then tie off (human hair braids).
This method keeps the ends from sticking out of the sides of the braids, which is so embarassing! When people from 10 feet away can see the demarcation where your real hair ends, that is just not a good look! It also protects the ends from rubbing against things.
Whew, I wrote a book!
Hope this helps