Fred T: You have that right! Most folks worry about the cold. And the battery draw is often higher when starting on a cold day, but the killer of batteries is heat. More fail in the summer. It is just less painful to pull and swap when the weather is good. Besides, who wants to reach under the battery to change the #5 and #6 spark plugs? Hate reaching over the fender and under the battery to get to those on my buddy's 57. If you hit something that can get to the battery support, well you might want to change where you are headed. Or at the very least, how you are getting there.

Steve H