I don't as much anymore.
I used to just for the chelation because I have hard water and I use no-lye relaxers.
But since I realize that my Lustrasilk Cholesterol has EDTA (for chelation), deep conditioning with it really does take away the need to use a chelating shampoo.
Now, what I do is do two lathers when I shampoo. Now, I do use a clear shampoo that does not have conditioners, oils, or silicone and then I use a moisturizing one. Both of those are sulfate free and chelator free, but neither is labeled as a clarifying shampoo.
I find that when I use henna, I need to use my real clarifying shampoo to help me get everything out.