For me, BHD (love the acronym!) are caused by any one of four things: I need a DT, I'm using a product that my hair doesn't like for whatever reason, he weather is changing (the transitions from winter to spring and fall to winter equal a couple of weeks of BHD until my hair gets used o the new humidity patterns), or I'm way overdue for a cut. Reasons #3 and #4 are why I've been a bit frustrated with my hair lately.
Sulfate/non-water-soluble silicone free since 8/16/10
Northern VA
Med-coarse, normal porosity, low elasticity
Dye-free since 11/2010