Injector Life Expectancy

[Hammerhead]

(12-01-2016 )Rig Wrench Wrote:  I've done all 6 in 100k on my 871. I have a theory that at the power level it's at the extended duration is taking its toll. I back up this claim with absolutely nothing, just all that makes since. Started getting a lot of rumputy rump on start up. Checked for bubbles, had on 3 front cylinders. shortly after systems arose again, back 3 replaced and problem solved. Only has just over 100k miles still, total

Help me understand your thought process...

The injectors are cam driven on an 871. (To me) That means that the injector travels 100% top to bottom every second rotation of the crankshaft. There are no electronics on the actual injector, the timing and metering are done externally. The only difference on the injector cycle is the amount of fuel volume in the metered & timing portion of the injector to control timing & injected volume. If I am understanding this correctly, then the engine work load plays zero effect on the number of cycles that the injector should theoretically last.
Yes I understand work/torque load equals heat, and heat shortens the life expectancy of intricate working components like injectors...but besides that, should all else not be equal?
If not, then what am I missing?