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.
From that drop-down menu, click on File Info (not shown here) and you'll get a pop-up window with information for that image file. Click on Advanced (last item) and then expand the 4th item from the tree.. Aux Image Number is the shutter actuation count for that particular image. The attached image is from CS3.