Which of these external hard drives will you choose to buy if you want a 1 TB memory regarding the fact that the price and the appearance (beauty) is not important?  Silicon Power Armor A80 External Hard Drive - 1TBSilicon Power Armor A30 External Hard Drive - 1TBSilicon Power Armor A60 External Hard Drive - 1TBSilicon Power Armor A65 External Hard Drive - 1TB Why and why not the others?Please just compare these four products and choose between them.  And if you want to buy a 2 TB external hard drive, which one will you choose. Again regarding that the price and appearance isn't important?  WDBU6Y0020BBK (Western Digital Elements External Hard Drive - 2TB) WDBBKD0020BBK (Western Digital My Passport Ultra Premium External Hard Drive - 2TB ) Why and why not the other?Please just compare these two products and choose between them.  Also I mean to compare the products from a technical view and the most important factor is their lifetime.I'm living in Iran and I can't use guarantee, supports or anything else.I just want to buy something and take the most of it?
I want to compare some external hard drives model and decide which to buy?
hard disk
RE: the Silicon Armor units:If you're talking about lifetime when operating in an ideal environment (good temperature, not a lot of hard impacts or water, mostly sitting still on a desk), none of the technical specs really give us any insight into how reliable the drives inside these enclosures actually are. Typically, a drive that does not suffer from any significant physical trauma or movement while in use will last for 5 to 7 years if used frequently, assuming there are no design flaws artificially limiting its lifespan. Even with military spec protective casing like these models offer, any hard impacts or significant movement while using it will probably reduce its lifespan by a large amount. Hard drives are too precise of an instrument to be thrown around; components will start to fall apart and lose their precision (and fail soon after) in short order.The only differences I could discern between the units were the levels of military spec (or lack thereof) certification, and the levels of IPX (or lack thereof) certification. The one that supports MilSpec and IPX7 is probably the best overall protected. That'd be the Armor A80.Also consider that the disks themselves could be low or high-quality, the firmware / disk controller could be low or high-quality; the connector ports could be low or high-quality; etc. which could affect lifespan of the device. If warranty service is not an option, you might want to shop around for more than one vendor. Also consider the opinions of both the original poster and the commenters here and think about whether an Enterprise-grade disk might be better (in some kind of portable enclosure).--Since you didn't state any criteria, for the WD disks I'll go with the My Passport Ultra because it's bigger and I (perhaps illogically) think that a larger disk is more likely to have some kind of padding / armor that'll make it more physically resistant to shock. ;-)