Hi
@summerof1990, I have worn braids/twists on and off for a
long time lol and I'm now at the point where I do my own braids, so I don't experience damage from them at all. I would almost say I don't recommend braids if you can't do them yourself or have someone who is a gentle braider. To answer your questions:
1. Braids don't "strengthen" the hair, but when done properly, they can help you to maintain and retain your growth, which has been the case for me. One thing you should know is that senegalese twists/braids can cause a lot of tension to the hairline, especially when done by braiders who braid too tight. Also if your hair is not prepped properly beforehand, i.e. blow dried near straight, your hair will be combed roughly by some braiders which will break your hair off.
2. I retain my growth wearing braids, because 1) I don't get them small and 2) they allow me to not have to fuss with my hair causing breakage through manipulation caused by everyday styling.
3. You can wash them--there are a bunch of videos on youtube on how to do it. I probably wouldn't wash them more than once every two
weeks as your braids will start frizzing up and looking bad real quick. Most important is to have a moisture spritz of some kind to keep your real hair moisturized. But if you work out a lot, by all means wash your hair, but focus on the scalp.
4. Breakage caused by chemicals will probably not stop just because you put braids in, in fact it can get worse if your hair is not in great shape beforehand. I would try to figure out what problems your hair is having first before installing any type of extensions.
Hope that helps.