Interesting thought ch_66. .. .From what I can find the on the Web and thinking about it, probably not.. .. .MTBF (Mean Time Before Failure) for modern drives is often given as ridiculous figures (400,000 hours is 45 years!) and doesn't mean that. One source says that the useful life of any given drive is 5-7 years (45,000 to 60,000 power on hours). IBM quote the life of their new drives as being 20,000 to 30,000 power on hours.. .. .Unless it is on a network server a typical hard drive isn't doing anything much except spinning - I'd reckon that my drives are actually seeking and reading/writing only about 5% of the time that they are running. In the days when memory chips were expensive and memory sizes small the OS used the disk as "virtual memory" and kept them pretty busy (try having a couple of apps active under Win95 on a 16MB machine and you can hear the drive thrashing). Now that most users have a minimum of 64MB of memory and often much more there is far less need to "page" active memory out to disk and back again so that the actual drive head mechanism is less likely to be working. Also modern OSs/BIOSes and drives spin down after a period of inactivity and. .only wake up again when the OS wakes up.. .. .So I guess we have to consider the spindle motor and the drive-head mechanism almost separately and then try and factor in all of the above. Parhaps the faster 7200 rpm drives have more spindle failures (they certainly run hotter)?. .. .I'd hazard a guess that on an average day a single security overwrite of a 50MB file would only add a fraction of a % to the overall head mechanism activity for the day and nothing to the spindle run-time.. .. .[Must now get beer to cool off overheating brain circuitry]