I've been shampoo-free for about 3 months. With shampoo I have extremely unruly hair, so unruly it's ruly . When I use shampoo I don't do more than run a comb through the hair occasionally to keep it from getting dreadlocks, otherwise nothing.
Without shampoo, it feels heavier and is less curly, so I have to comb it. But, no dandruff, and people actually have commented me on the looks of the hair. So, I'm happy.