Here's how: 1  Stand with your feet shoulder-width apart and knees bent slightly. 2  Lean forward, placing your hands just above your knees. 3  Round your back so that your chest is closed and your shoulders are curved forward.  Then arch your back so that your chest opens and your shoulders roll 1  back. Repeat several times.
Typically this count is between 100,000 and 300,000 shutter actuations, with the latter limit associated with the EOS-1D models. In fact, the Camera Shutter Life Expectancy Database is a really neat user-based site for DSLR models of several brands, including Canon.
Each Exposure Value, or EV, represents any of many different but equivalent combinations of f/stop and shutter speed. For instance, 1/250 at f/8 is EV14, and so is 1/125 at f/11. 1/125 at f/8, one stop more exposure, is EV13, and 1/250 at f/11, one stop less exposure, is EV15.