Hi Hotze! And, suited to anyone interested too. This does not apply at all. MTBF is stat based on random pick and project it and it's bandied about purely for marketing/relibility, *Hmmtph!*. A year is about 8760 hours long and my real experience tells me average especially for low end to barely medium end have average of 3 years at MOST due to bit of substandard production used to keep costs down. I have talked to someone and told me the major differences in controlling this reliability (means it to last years and years and years) was in all types of balancing, bearing runout, top quality bearings and has rubber seals on them, coated housings and very rigid design, spindle axle runout, spindle runout all made to VERY TIGHT specs that micropolis used. Also the design of heads arms and balance, flexing, damping and pulse train profile to make it "cushy" seeks yet rapid is very important to lifespan of the HD. I've opened all kinds of hds including several failed micropoils 13xx series. I understood why. Tandon/early 40mb WD's used fine regular ball bearings with bit looser specs, rack/p gearing, poor designs, all of them died in short order, I have not seen one that is still alive locally or at other few cities, same with miniscribe also to lesser degree except for their rack/p gearing the worst one. WD also did use that quality even with voice coil until recently (hopefully!), ditto to early st251 and st125 series as well as few early ST1144A/ST3144A series. DaeYoung indeed died young true to its name, ditto to Kalok and Kocera. I did open the few Quantums including ELS 85, this used a sealed bearing and manufacturing finish and all was pretty good as top end types. I was glad that Quantums learned their past mistakes quickly (My friend in computer business sold over 300 quantums of all kinds from low end to mid and none came back. There was one hd that dropped down flight of hard stairs that worked for short time...true story.) as well as Seagate if even bit slower. Maxtor is hit and miss and still have compatiabity problems, (One brought up appox under 40 850mb, MTBF was in that range Hotze indicated, lot and all of them died towards 1 year then failed in large bunches, none survived past a year and half and they're not that heavy use! Primarily in school use in their PC's teaching s/w not h/w!) Have a 1355 w/ date production of about 1987 and couple of CDC's and one Priam that had made when QC was high. All except for 1355 are appox 60-80mb full height catorgy. There are several failures recently related to installer errors: found several that used WD type seal that use special tape band to seal out seam that meets by both top shell and the chassis, ditto to several seagates using this This is no excuse that blamed on sharp cage's edges. All one is to be more careful and take and install it carefully without tearing those sealing band! Several quality hds failed but I was able to tell it were caused by installer error and imporper install. (Microscience did a research and found that 1" drop on hard surface was enough to subably damage it. I also chalk that up to installer skipping (I hear it!) during installing hd's using philips screws along with general bangs during handling.) General warning issued: Quantum fireball ST series notch cutouts to allow normal PC screws have ridden of, requiring stubby screws. But as a general rule, I apply this stubby screws appoach to all hd's. Well, for now, If anyone have anything more to point out, I can try to point out and see other side experiences. I as being curious tinker and a quest for failure analysis is valueable experience and more importantly, indictor of hd makers' commitment to contiuned QC on all levels. Jason D. nip!