I have a couple different bags for my BOBs. My Primary BOB is a simple messenger bag and I do keep a few clothing articles in it; SKD Orange Ball Cap, Rail Rider's Eco-Mesh Shirt, Marmot Precip Jacket, and a spare pair of socks. I also always have a pair of hiking boots attached to my BOB because I normally wear flip-flops or Keen sandals when I am not at work. A pair of leather work gloves and sunglasses are also in my kit.

For the winter (in AZ) I add a pair of OR PL 400 gloves, OR ovo Watch Cap, and a Wool sweater (in place of the Rail rider's shirt.

I have a separate bag for real cold weather travels that is bigger and has among other items, a hard shell (top and bottom), base insulating layer (top and bottom), heavier gloves/mitten over gloves and hat, snow claw, sleeping bag, foam pad and bivy sack, Gore-Tex boots and extra socks.
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"Trust in God --and press-check. You cannot ignore danger and call it faith." -Duke