Why do lots of people say mining is 'bad for your hardware'?

[ChefBorjan]

Correct me if I'm wrong, but I'm fairly sure manufacturers design our computers to run 100% non stop.

If you are rendering a complicated 3D scene, or performing complex simulations then you will be maxing out your hardware no? And when people do this, I'm sure others aren't turning around and saying 'oh watch out your computer will explode thats not what these are meant for'.

Yes, some computers will perform better than others or have better cooling, but the manufacturers surely aren't making products that will break if you simply use them. Thermal throttling or something should kick in right?

Or is hashing and mining something more stressful? 

[greyhawk]

Correct me if I'm wrong, but I'm fairly sure manufacturers design our computers to run 100% non stop.

No, they don't. They design for "typical use".

[iram9093]

Most of them aren't.

[ChefBorjan]

Most of them aren't.

As in most of them aren't saying it? I get that it may be a vocal minority though...

...like above! 

[lch]

You use your graphics card for longer period of time when mining.

[cp1]

Consumer products are only designed for intermittent use.  Look at the difference in price between server/enterprise quality parts and consumer quality parts.