Do you give your hard drives a finite lifetime and unconditionally replace them by a certain date (say, the end of the manufacturer's warranty), or just wait until they fail?
I have a RAID5 array so it's redundant - one drive failing will not lose any data - but I'm not sure about twiddling my thumbs until the drives fail. By then you probably won't even be able to buy a 300GB drive anyway.
Thoughts?