Shutter count is generally a useful service reference on both Canon and Nikon, but it should not be treated as an unchangeable lifetime total.

Based on the answers, there’s no strong evidence that Canon is fundamentally more reliable than Nikon here. For both brands, the count is typically stored in camera memory and may be reset during service, especially if the shutter or related electronics are replaced. That’s similar to an odometer being reset when major parts are changed.

Firmware updates do not normally reset the count, and one answer reports a Canon firmware update that did not affect it. Still, exceptions may exist for some models or specific repairs.

Also, shutter count is not necessarily the same as the number of images saved, because the shutter can cycle without a final photo being recorded.

So the practical takeaway is: if a camera has not had major service, the shutter count is usually a good approximation of use. But after repairs or component replacement, either Canon or Nikon counts may no longer represent the camera’s full historical total.