Because K2's got this flat spot on the back of her head, and it's kind of bugging me out. It started early; she'd almost always turn her head to the right when we'd lay her down; and while we'd always make sure she had a full range of motion in her neck, and we'd turn her head to the left sometimes while she slept--minor/insignificant solutions at best--it hasn't really had any effect. We figured that spending more time on her stomach and sitting up would lessen or diminish the flat spot, but it hasn't.
It's not really that noticeable; my wife spent a few weeks not believing it was there at all, and she did most of the baths, when K2's hair was wet enough to really see it. On our last visit to the pediatrician, our normal doctor wasn't in, and his dimwitted partner couldn't understand what I was talking about until I pointed it out, and then she just said, "Oh. Go see the neurosurgeon."
So how flat was your kid's head, and what'd you do about it? I'm not opposed to the kid rocking a plagiocephaly helmet, as long as it's painted awesomely enough and doesn't have freakin' mermaid stickers all over it. But even writing about helmets in the abstract [and three years ago, though as the comments on that post show, it's very much a live discussion], I find myself at a loss for what, if anything, to do.