Can the USB stick last that long? I heard the electron will migrate and leak out. The information will be lost.
I have had some problems with usb sticks before in my life. I had some music on it but even tho I deleted ther music on that usb the space was still not being empty.
The USBs are not a good idea to store your private keys or wallet.dat file(s) because it can be self corrupted or lose the information within 10 years, so the best idea to store sensitive data is to have many backups physical and virtual(like dropbox google drive etc.)
It is better if you are going to put always a back storage for your important files, I'm using yahoo for back upping my files.
Especially those files with important information.