Does my iMac check for new Mail messages while asleep?

Question

The Energy Saver settings on my iMac are to sleep the display after 15 mins. and the computer after 20 mins. and I do check "Put the hard disk(s) to sleep whenever possible."
Two questions:
1. *Is permitting my hard disks to sleep helpful or harmful to my iMac in the long run?* I care less about energy costs than the long-term health of my computer. So what's worse: spinning the hard disks down (causing wear and tear) or constantly exerting the disks by never letting them rest?
2. This is the key question for me at this moment: *while asleep, does my iMac retrieve new email messages?* This is an issue because I have a number of Rules I've setup within Mail on my iMac that move messages to certain folders. So if the iMac is asleep while I'm out and about, these messages clog up the inbox on my iPhone's Mail app until I come home and wake the computer (I have a gmail IMAP account). Also, does checking the option to put the hard disk to sleep affect my iMac's behavior in retrieving email while the machine is asleep?
I'd appreciate any clarification.
Grant

Answer 1

1) There are lots of arguments about all kinds of esoteric questions and whether you should spin down the drive or not sounds like a good candidate. Drives do die of course, but in the greater scheme of things you and I are more likely to either replace the drive for something larger or replace the computer before that drive dies.
2) If your computer is asleep it cannot check for mail or do anything else for that matter. End of story. Assuming you have broadband, when you restart/wake your computer it may appear that mail has been accessed while the computer was asleep but that's because your mail application probably checks as soon as the computer was awakened/restarted.