>>3273332Here's a fairly extreme example of how plastics can distort over time.
This knife was made in 1944. When it was newly made the "scales"--the textured black plastic covers on the handle--completely covered the steel parts underneath. However, as it has aged over the past 70+ years the plastic has shrunk. It's perfectly solid and not brittle in the slightest, but you can clearly see the steel showing around the edge of the plastic, especially at the left-hand side of the pic. The plastic shrunk over time but the steel did not. You can see the steel all around the edge of the handle. Now imagine shrinkage like that happening to the critical parts of a modern camera or lens.
Plastics distorting over time is a fact of life. It happens. That said, it doesn't really matter much. Even today's latest and greatest DLSR will be considered long obsolete before significant deterioration occurs due to its plastic parts. But to think it will NEVER "break" in some sense is very silly. Everything deteriorates with time, even the pyramids.
