i have been shampoo free for about 2 years. every few months i use some baking soda in water to rinse it if it seems actually dirty or greasy and if it is getting to tangled i rinse with vinegar but otherwise all i use is water. before i lived here i tried to go shampoo free and my hair always ended up so oily i would break down and use shampoo or just a bar of soap and vinegar rinse but i did sort of wean my hear and use soap or shampoo as little as i could manage. i think water quality and ph effect how easy it is to go completely shampoo free because as soon as we moved to this house which has very nice well water i found my hair did a whole lot better and just stopped needing the once in a while (maybe once a month or every 3 months) shampoo it was getting.