As an amateur photographer-hobbyist, as well as a HL enthusiast, I have 2 camera bodies. The second one is not a top of the line SLR, but an older model with a mechanical shutter which only needs batteries to run the metering. In the cold of winter, the batteries may die, but the camera continues to work. Only cost me $40 used at auction.

I don't recommend this for everyone, unless you are really into photography. Keeping a second battery is the best insurance for all weather conditions.