Why does the quality of photos on iPhone deteriorate?

Question

iPhone

Could you tell me what is the reason for the deterioration in the quality of the photo on the iPhone (5c), the device is 3 years old.
When I bought I could not get enough of the quality, I shot really cool.
In total, I think no more than 1000 photos were taken on the rear camera.
Now the phone shoots disgusting.
I remember that the same thing happened to me with the iPhone 4s after some time.
Is it programmable aging which, for example, is included in a software update?

Answer 1

Could you at least attach examples of photos.