Which Is True for 24/7 Sleep? Hard Drive Could Fail Because It's Constantly Spinning or Because It's Suddenly Switched ON

Question

Hi. It's sleep vs. shutdown again. I read some computer components are better off on sleep mode, some components are better off shutted down. If each component lasts longer in sleep mode and some shutted down, what then is the best for Macs as a whole?
If it's sleeping for 24/7 won't the hardisk for example wear out more because it's constantly spinning. Won't the power supply wear out more because there's some heat? On the other hand with shutting it down then turning it back on, the components could fail because of the sudden expansion they say from cold components when it's switched ON (or sudden jerk to moving components when it's switched ON)?
Doesn't sleep turn off components anyway like they were shutyed down so even if you use sleep, there's still a possibilit of it expanding from a cold components to warm components (or sudden jerks with components like in the hard drive)?
Apple's manual says put it on sleep. What do they mean exactly? Are the recent Macs designed be ON 24/7 for years? Or do they mean put it to sleep mode as must as possible in a day but still shut it down at some point?
There should be a more thorough scientific study on component failure for Macs and computers already on sleep vs. shutdown. Thank you in advance. Gbu.
What're your experiences between sleep and shutdown. Which components lasted longer for sleep, for shutdown?

Answer 1

baltwo wrote:
I never sleep desktop computers or their HDs, only their displays, run 24/7, and have only had one HD faiurel the past 11 years. Most electromechanical devicesw fail during power on.
Some questions: Is it possible to keep the drive platters constantly spinning? Doesn't most drive firmware set the drive to spin down after about 10 minutes of inactivity? If this is the case, wouldn't it make the question moot, at least as far as drive life is concerned? Drives have a finite number of spin up/ spin down cycles. I don't know if you get around this by never sleeping the computer. If the computer is sleeping, the drive is spun down and the heads are parked. If the computer is set to never sleep, will the drive spin down anyway?
In additon, even if the platters can be kept constantly spinning, don't we have to figure in the long term damage from the extra heat that generates, which might make the whole thing a wash?
Message was edited by: WZZZ
This would appear to support Baltwo's and Dennis's usage scenario. But it doesn't address the drive firmware question I raised, above.
It is better to spin down the hard disk drive whenever you can to       reduce stress on the spindle motor.
Truth :
Normally, the platters are spun up at start up and kept spinning           after that. The spinning up process is the most taxing part on the hard disk drive's spindle motor. Maintaining the spindle speed thereafter requires a lot less           effort.
If the platters have spun down and you need to read/write something           on the platters, you will need to spin up the platters to full speed         before you can read or write. Therefore, if you want maximum performance, it's better to keep the hard disk drive spinning.
However, spinning down the hard disk drive during periods of inactivity can not only reduce power consumption, it can also reduce the heat produced. The reduced thermal output will increase the longevity of your hard disk drive.
So, while spinning down the hard disk drive will not reduce stress on the spindle motor, it can reduce the hard disk drive's power consumption and thermal output as well as increase its lifespan.
http://www.techarp.com/showarticle.aspx?artno=84&pgno=3