The great thing about memory sticks is that they are very portable, and have a relatively good transfer rate. This makes them excellent choices to transfer files from one computer to another (Eg: from school to home), but their unreliability means that they are poor choices to store data for an extended period of time.
To offset this unreliability, it is recommended that you copy files to and from your memory stick, but never run or edit anything on it. Here’s an example:
Fred has started work on an assignment at school. He finishes up for the lesson and saves the file to his ‘My documents’ drive located on the server. He wants to continue working at home, so he manually copies the file to his memory stick. That night Fred wishes to continue work and inserts his memory stick. Instead of working directly on the file, he copies it to the desktop or an allocated space on the hard disk. From there he can work quickly and effectively on the file. Once finished he can then copy back the updated file onto the memory stick, possibly renaming it to another version. At school the next day, Fred continues his assignment by copying the previous night’s file onto his ‘My Documents’ drive and working on it from there.
In this example, the assignment will exist in multiple locations and have multiple versions. If at any point the memory stick dies, or even the home computer or school computers become inaccessible, the file will be recoverable with a maximum of a few hours of work lost. For times when you REALLY need that file, even copying it to multiple memory sticks is a wise choice. They don’t need to be super expensive, anything in the ~$10-$20 range should be sufficient for a simple transfer.