eli5: If modern computers and smartphones etc have no moving parts, then what causes their performance to steadily deteriorate as they age?

Question

eli5: If modern computers and smartphones etc have no moving parts, then what causes their performance to steadily deteriorate as they age?

In: Technology

Answer 1

The parts may move less, but now they’re often extremely tiny and delicate. A number of factors are at play with possible damage: oxidation,  moisture, dust accumulation, repeated stress (vibrational or thermal), and so on. Over time, very tiny parts can fracture, short circuit, and degrade. 

For some like memory components, eventually solar radiation and such will even come into effect.