Try it in your word processor. It is useful there also. My friends tell me that I should convert from the old FAT to the new FAT32. This is important with hard disks larger than 500 Megs. A cluster is the smallest unit of storage that can be placed on a disk.
Smaller clusters are more efficient in the use of disk space.
Before making any decision, the smart thing to do is to check what your savings will be. The Windows 98 installation CD offers the FAT32 Conversion Utility to calculate this information for you. Double-click on the Fat32win.exe file, select a drive, and click Scan. There will be your answer. Your final decision should be based on whether you need the extra disk space.