I have a number of older drives (3-5yrs old) that I use to store data that isn't necessary to have available all the time. Some of the data is backups of data that's on my internal HDs), and the rest is stuff that is NOT on my internal HDs but that I back up (so I always have 2 copies). These older drives don't get a lot of use. I don't know enough about how drives fare over time to know whether the hours of actual spin time are more important than the elapsed time since manufacture. The drives that spin most the time I replace on a 3-4 year cycle. Because these drives are not used much, the fact that they have slow access times is not important to me. Is it reasonable to keep the older drives in use until they crap out, or should even infrequently used drives be on some sort of replacement schedule? And how is the quality of current production drives in comparison to that of the their forebears?