Should you use a leave in conditioner after using a rinse out conditioner ?
There's no such thing as "hair rules" about these things-- it's about your preferences and what your hair needs. I have high porosity coarse hair that gets too limp when over conditioned, so I personally prefer one or the other. But other times my hair needs more moisture and I use both. Also, the amount of moisture delivered by the particular product(s) determines what I do. It's all a game of try it and see what works for you.