Life Expectancy for camera

I was wondering what the Life Expectancy for a consumer camera is. We generally never turn our Canon hf200 off (been 3 years)

I had a Canon GL 2 I had connected via FireWire and never turned off for about 3 years. The camera never actually stopped working, but the FireWire board finally died.

I guess it depends on what type of cameras you are using. I had 3 Panasonic's that went bad on me in the past