Contrary to the earlier perception that it is better to Turn Off the hard drive if the PC is to remain unused for sometime, the current advice at many sites is to let it remain on. This,they say, is due to the fact that more damage/wear and tear takes place during switching "off and on" than during uninterrupted running. 2. Is that view correct?? 3. Does it remain true even if the screen saver continues to run?? -

Well........ I have been turning my systen on and off for the last 7 years, 2 to 4 times a day, and had no failures, all original parts but for a mother board that was fried during a thunder storm, 3 other computers just across the street were fried the same night. However I live a warm part of the world and stopping starting a system in cold conditions may cause problems I suspect. Avagoodweekend. Growing old is unavoidable, growing up however is stll optional

It doesn't make much difference mate. Adam

I totally agree. A hdd circuit board can have problems at any time, a motor can go to hell, or a physical crash can damage the heads or platters. My last worry is turning it on and off or trying to leave it on. Skip

It's generally true that constant on/off is more damaging to a circuit that just leaving it on. But it's usually physical wear and tear that cause a drive to fail. I think the option to have the HD spin down in periods of non-usage is safer to its electronics than the abrupt power on or off experienced when the PC is turned on or off. When it's spun down the circuit board is still being powered so no change of state is involved. It might be a litte harder on the motor but you have to weigh that against damage caused by continual usage. Also, whether to leave the PC itself running or turn it off should depend more on usage than any strict rule. If you only use the computer occasionally it'd probably be best to shut it down when it's not in use. If it's being used most of the day or several times during the day you may want to leave it running. Except when a screen saver first loads, there is no affect on the hard drive.

I believe that issue here is the wear on the bearings. The greatest load on these is when spinning up especially if from cold. Like a light bulb, this is where it will fail. But also like a light bulb, the constant wear when it is running does the majority of the damage. As suggested by the location of the controls to spin down the HDD, it is a power saving consideration. You wouldn't leave your car motor running overnight to make it easier to start in the morning! Of course hdds you considerably less energy to run (a few watts). I did once replace worn bearings on a hard drive. This was a 80's server which was always running. In answer to your question, maybe.