I bought several WD's 6-7 years ago, and had a 40% failure rate. It seems it was a bad batch though, since The drive in that was in my current machine worked without issue 24/7 for 3.5 years. I just recently replaced it for nothing other than space and speed considerations. Of all the WD's I currently have installed in the field, and that's about 105, I have never had a failure in a drive less than 5 years old. I HAVE had 3 Maxtors and 2 Seagates fail, however.