I find claims of X years to be nothing more than marketing hogwash.
Ever notice that media products that make these claims are ALWAYS the worst products? Just think of hard drives, CD-R or DVD-R. Furthermore, read the fine print. These are NEVER guarantees!
Quality products have sensible lifespans, the end.
I'd much rather use a good product from a known-good manufacturer. For USB thumb/flash drives, that means several quality brands like HP, Kingston, PNY ... and yes, ever SanDisk -- sans the pointlessly expensive version!
I buy all of mine from
Amazon:
http://www.amazon.com/USB-Flash-Driv...&tag=thdifa-20