How much bandwidth is necessary for my needs?
This purely depends on what your equipment is being used for. Examples of server usage that may require large amounts of bandwidth are database driven servers (such as ecommerce sites), web servers and upload sites. Any server that is being utilised for a site with heavy traffic is likely to need large amounts of bandwidth. You are unlikely to need large amounts of bandwidth if you are running a basic website from your server or you are using your server as a backup device, as backups can be scheduled so as not to exceed limited bandwidth limits.