I am a 4 natural with small penspring like coils and z-shaped waves.
SLS are a no-no for me because they all make my hair feel like wet hay instantly. The followint SLS-free poos I've tried so far have not given me this problem (although they are still a bit drying). I use these whenever I have some in my house: Giovanni SAS, Curls Cleansing Cream, TJ Nourish Spa, Suave Coconut. The TJ and Suave are more drying than the first two, IMO.
I shampoo once a week, every week using a non-sulfate shampoo. I have been using the Cleansing Cream in the Curls for Target line. It is pretty good, however, I like to use a lot of shampoo, and this may only last me two months.
I need to shampoo, or else my scalp gets itchy, my hair feels overly coated with my leave in that I apply 2-3x a week, my hair starts to smell like mold (i think at least), and my hair starts looking dusty and dull black.
Also, there are benefits to shampooing. When I shampoo, my hair color becomes darker and able to sheen and sometimes shine with all its might. My deep conditioner that I apply after I shampoo works so much better than if I just co-wash or rinse my hair only with water-- I can really feel the difference instantly and my hair is moisturized longer.