Disk Quotas are a management feature to help administrators, not users. In many environments, users will fill whatever disk space is available to them without thought to the costs associated with it. Quotas encourage users to do their own "housekeeping" on their network shares and provides a fair allocation of system resources. If users or managers need additional space for legitimate business reasons, it is easy to allocate those resources and plan for growth. What you're trying to prevent is users backing up their entire workstation hard drives to the network, or storing large personal files such as videos, images, music files or other data that isn't business related. This useless data can take up hundreds of Gigabytes of data on a network, quickly filling servers, and adding to the backup and archival storage costs.
This was first published in March 2004