Expected lifetime of a digital camera...

Interesting question. We know the shutters are rated at about 100,000 exposures or more, but how about the CCD.

As the photo sensitive sites are photo diodes I would guess that the life expectancy might be similar to that of say a LED, another form of diode. That might be 10,000 continuous hours, so at 1/60 second per exposure that makes 600,000 exposures if my shaky maths is correct.

If that's anywhere near a viable guess then I think the camera will be upgraded well before then...

I guess the expected lifetime of a Dslr is the same.............as the time you can withstand the urge to upgrade
Martin.

Yep, just take some pictures and relax...

As the mirror doesn't rise until you press the shutter, no light can reach the sensor until that point.

Metering is done with a small cell using light bounced off the mirror.

G

the whole thing works just like a film SLR except that the film is a digital sensor. Unless you are talking about live view on the K20, the sensor is only active as long as the shutter is open (plus dark frame aquisition if activated).

I strongly suspect the shutter will wear out long before the sensor, but at the very least my K10D has taken 9500 shots with no visible ill effects so at your current rate you should be ok for at least 3 years.

My advice is stop worrying and start taking great photographs