No, 2.5 to 3 months max for the best retention. There are many threads about women protective styling with braids. I'm one of them. Success with braids is dependent on many factors, mainly getting them installed correctly and being consistent with moisture while in braids.
The hair is locked within the braid, but you can still do all those things for your real hair. They key is that everything must be liquid for it to penetrate through the braiding hair to your real hair. You have to dilute your shampoo, only use liquid leave ins, etc.