A magnet placed on or near your disk is begging for data loss. My mom once took a disk from her kitchen table and stuck it to the fridge with a magnet. Needless to say, we were unable to recover anything from that fiasco. Get a floppy jewel. Available at the University Bookstore or Team Computer, a floppy jewel will greatly protect your diskette from a number of threatening factors.
Floppy diskettes are far from floppy.
Don't put your disk in your back pocket and sit down. Your car does not care about your documents. The car is never a good place for your diskettes as they could be exposed to extreme heat during the summer, and extreme cold in the winter. Also, try to keep your disks away from sources of heat like radiators, computer and television monitors, your oven, etc. Scan for viruses.