Flash drives do indeed wear out, but only from being re-flashed. The write count is what kills them, and it varies by type, make, and quality, but is generally 10,000-100,000 writes. A *KEY* point when mounting a flash drive under linux is to use the "noatime" option to switch off writing access times. If you do not do this, then you will have a write on every access. Not only will this eat up your drive, but it can make it slower, especially when copying a lot of data.