I did bigen yesterday, so far no breakage (that I wasn't already getting due to an overlapped relaxer). I took the risk anyway because I wanted to enjoy my shoulder-length hair as much as possible while I still have it.
I used oriental black. They aren't kidding, my hair is that deep, dark, true black color. I LOVE it. Now I feel like spraying on some serious shining spray or using some serum and flat ironing it out to really get that shine.
As for deep conditioning, I did one after I rinsed the color out. I used an avocado mashed up with honey and coconut oil, and followed that up with MM nurturing Creme. ONe thing I did notice--even though the water ran clear after rinsing out the dye, when I took off my plastic cap (I used the avocado mixture with heat) alot more dye ran out. My hair is still deep dark black, though. Still I think that deep treatments with heat will cause the color to fade over time, and that may be the culprit in the 2-3 months fading NAY noticed.
However, bigen is not expensive and I will just plan on using every 3 months , about a week after touchups.