By the letter, they are off-topic as being "Android independent hardware questions" – as Matthew correctly pointed out with his comment on the question itself. However, "by the letter" that would also apply to several of our battery-life and battery questions (e.g. When should I start charging my Lithium battery?).
While I originally held the context might make a difference, that's hard to find for material durability – while with the battery example, it falls into "daily use of your Android device" (maybe into a gray zone, though).
So I tend to follow Matthew's reasoning, declaring such questions (as described by the question above) off-topic.