It amazes me how long the battery in my 1D Mark II actually lasts in between charges. I charged the battery for a day of shooting, got wrapped up in whatever and went back to the camera and days later, it still fired up and showed a full battery. This workhorse is amazing after all these years and although she has seen it's share of red carpet events and shows her age, this camera was gifted to me by a good friend of mine. I have a more current model camera but I love this old "Betty" and the way it sounds when I shoot multiple frames plus the sentimental value alone makes her valuable. The 1DXMark II is the current workhouse for the busier Canon shooters but for now, I love Betty.