I found this article at usb.info:-
The life cycle of a flash drive is a question which has been around for a long time. There are many factors which contribute to the longevity of a flash drive. Today, lets look at some.
I feel there are three main components which effect the life cycle of a USB flash drive.
Memory type
USB connection
Chassis or case
Flash drives use two primary types of flash memory. There is SLC and MLC memory. SLC is Single Level Cell memory and MLC is Multi Level Cell memory. GetUSB.info did an in-depth write-up about SLC and MLC flash memory if you’re interested, but for this article we have:
SLC memory is good for about 100,000 write cycles.
MLC memory is good for about 10,000 write cycles.
Most UFDs use MLC memory because it’s cheaper to make and allows manufacturers to offer more storage in a smaller space. It’s difficult to figure out which type of memory a UFD has, but it doesn’t matter anyway - most flash drives are more limited by other factors.
Next, lets look at the limiting factor of the USB connector. This is the actual socket which connects the UFD to the host computer. Doing some research, most USB Type A socket manufacturers provide a specification called Mating Durability. The spec is around 1,500 connections. WOW, that sure limits the life cycle, but I doubt many would connect the UFD to a host over 1,500 times.
Last, the chassis or case help the USB life cycle. The chassis helps the UFD look cool, but also provides a small amount of protection against wear-n-tear. UFDs are exposed to all sorts of shock. Whether it be physical shock or electric shock, it’s important to treat your UFD with care. True, there are some indestructible flash drives out there, but the point here is try not to let external factors instantly destroy your drive. The best method for shock protection is A) don’t drop, slam or smash your UFD and B) keep the cap on so the connectors don’t rub or touch another object which could create electric shock.
So, to sum everything up: Given you don’t physically ruin your drive, you have about 1,500 connections and about 10,000 write cycles before you can expect the USB life cycle to become questionable.
..... The full article can be found here:- http://www.getusb.info/what-is-the-life ... ash-drive/
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randomchaos wrote:- I've seen from 10,000 to 100.000 to 1,000,000 quoted for the write cycles [on different sites!], but if one maybe takes the "conservative" and safer figure as a guide [10,000] ......!?! - I personally would take the lowest figure as a guide. - As for the "Mating Durability", if you used the flash drive contents often, then you may [or may not!] tend to leave it in the pc a lot too ..... or forget to disconnect it! So although the figure of 1500 physical connections to the pc is relevant, it's not THAT relevant...... IMHO!!