The Insider Picks team writes about stuff we think you’ll like. Business Insider has affiliate partnerships, so we get a share of the revenue from your purchase. A parka is a wintertime essential for much of humankind. Without one, layering enough to stay warm can be a nuisance. But oh, what a sea of decisions: How thick does it need to be? Do you need the hood to be lined with fur? How do you feel about faux fur? We’re still left to ponder pockets, length, and lining. And what on earth does “fill power” mean? While all of the above may or may not be critical decisions, they’re all things we have to consider. A parka is something we hope to invest in for the long haul, and a parka that doesn’t last more than a few seasons is, in my humble opinion, not a parka at all. Let’s start with the filling, and what fill power means, exactly. That’s how many cubic inches of loft one ounce of a given variety of feather produces. Fill power does not necessarily tell you how warm a parka might be because it doesn’t denote how heavily packed the down is inside your coat. What the fill power of a down does tell you is how well a certain typ...